The last of the year's four Grand Slam events has been completed, providing an opportunity to issue updated grades for the top tennis stars in 2013.
Things are starting to come into focus, with Serena Williams and Rafael Nadal establishing themselves as the top players this year. But does either deserve an "A+" for their work this year?
Our grades are based on 2013 competition only. Wins and losses were the primary factors used in sizing up each player's year, with Grand Slam events carrying the most weight. However, the expectations for the player, as well as the direction of the player's career, were also considered when issuing the grades.
We chose seven women and seven men who warrant star status at the moment and counted down to the player who received the highest grade.
ATP Ranking: 6
2013 Match Record: 35-12
2013 Grand Slam Results: Australian Open semifinals; French Open quarterfinals; Wimbledon second round; U.S. Open fourth round
Assessment: Roger Federer's plan to cut down on his schedule to be mentally and physically prepared for the Grand Slam events did not work out as planned. Quite simply, 2013 has been his worst year since 2002, when Federer turned 21.
That was the last year he failed to reach the final of any of the Grand Slam events. He no longer resembles the player who won a record 17 Grand Slam singles titles.
Federer has reached the final of just two of the 13 tournaments he's entered this year, winning only a grass-court event in Germany. He is 0-6 against Top 10 players since beating Jo Wilfried Tsonga at the Australian Open in January.
His fourth-round, straight-set loss to Tommy Robredo at the U.S. Open and his second-round loss to 116th-ranked Sergiy Stakhovsky at Wimbledon in his final two majors of the year were particularly sad. At age 32, Federer's time as a major force seems to be over.
ATP Ranking: 7
2013 Match Record: 35-12
2013 Grand Slam Results: Australian Open third round, French Open did not participate; Wimbledon semifinals; U.S. Open second round
Assessment: Juan Martin del Potro's semifinal berth at Wimbledon, where he lost to Novak Djokovic in five sets, followed by his victory in Washington, D.C., suggested del Porto might have regained the form that helped him win the 2009 U.S. Open. However, his rise was derailed, at least temporarily, by a second-round loss to Lleyton Hewitt at the U.S. Open.
That loss seemed to turn his year around. Instead of a second straight strong showing at a Grand Slam event, del Potro ended up getting past the third round in only one major in 2013. His only 2013 tournament victory other than D.C. came in Rotterdam back in February, and he has reached the final of just three of his 13 tournaments this year.
He beat Andy Murray and Djokovic in consecutive matches in March and is 3-3 this year against players ranked in the Top Four. The potential is still there for the Argentine, who does not turn 25 until Sept. 23.
WTA Ranking: 4
2013 Match Record: 45-14
2013 Grand Slam Results: Australian Open quarterfinals; French Open quarterfinals; Wimbledon semifinals; U.S. Open fourth round
Assessment: Although Agnieszka Radwanska continues to have problems in the Grand Slam tournaments, she is getting better in those events. She has never won a Grand Slam event and reached the final of only one (2012 Wimbledon). But this year, for the first time, she reached at least the quarterfinals in as many as three of the majors.
Radwanska won her first two tournaments of the year and has not won one since. She has a 4-6 record against Top 10 players this year and has six losses to players ranked outside the Top 20. This was probably the best year of her career, but the 24-year-old Radwanska won't be considered an elite player until she does better in the majors.
ATP Ranking: 10
2013 Match Record: 41-16
2013 Grand Slam Results: Australian Open fourth round; French Open quarterfinals; Wimbledon first round; U.S. Open semifinals
Assessment: Stanislas Wawrinka may be the most intriguing player in the world at the moment. Most of his 2013 results, including a first-round loss at Wimbledon, leave a lot to be desired. However, his strong showing in a five-set loss to Novak Djokovic at the Australian Open and his impressive performance at the U.S. Open suggest he is trending upward.
His results over the remainder of 2013 may indicate whether his straight-sets victory over Andy Murray in the U.S. Open quarterfinals followed by his tense, five-set loss to Djokovic in the semifinals were a fluke or an omen.
Wawrinka, 28, has won only one 2013 tournament, and that was a clay-court event in Portugal in which none of the top three players participated.
He lost his first four matches of the year against Top 10 players, but is 7-4 against that group since. He is 2-0 against Murray in 2013 and took Djokovic to five sets twice in Grand Slam matches Wawrinka could have won.
WTA Ranking: 5
2013 Match Record: 37-12
2013 Grand Slam Results: Australian Open runner-up; French Open second round; Wimbledon quarterfinals; U.S. Open semifinals
Assessment: Just when it seemed the career of the 31-year-old Li Na was on the decline, she rebounded with a strong summer. Her only Grand Slam title came in 2011 at the French Open, but she struggled through the clay-court season this year.
She bounced back to reach the semifinals of all three hard-court tournaments she played after Wimbledon, and she had her best showing ever at the U.S. Open after years of inexplicable futility at Flushing Meadows.
She had dropped out of the Top 10 last summer, but her current ranking is just one spot below her career high, which she held for several weeks in the summer of 2011. Her only tournament win of 2013 came in her first event of the year, and she has a 4-7 record against Top 10 players.
WTA Ranking: 13
2013 Match Record: 32-19
2013 Grand Slam Results: Australian Open semifinals; French Open fourth round; Wimbledon quarterfinals; U.S. Open fourth round
Assessment: Sloane Stephens started the year ranked 38th and is now on the cusp of a Top 10 ranking. She might get there by the end of the year. With Serena Williams approaching her 32nd birthday, the 20-year-old Stephens has become America's top hope for the future.
Stephens' impressive results in Grand Slam events suggests she's approaching stardom, but her inconsistency in other tournaments has slowed her ascent.
She has not reached the final of any of her 18 tournaments this year, and she has five losses to players ranked outside the Top 50. On the other hand, she is the only player in the world who has beaten both Serena Williams and Maria Sharapova in 2013.
WTA Ranking: 7
2013 Match Record: 22-14
2013 Grand Slam Results: Australian Open third round; French Open third round; Wimbledon champion; U.S. Open did not participate
Assessment: Other than winning Wimbledon, Bartoli did nothing of significance in 2013. She failed to reach the semifinals of any other tournament. Bartoli did not face anyone ranked in the Top Five and lost both her matches against Top 10 players.
She announced her retirement from tennis on August 14, but she has not ruled out a return, according to The Telegraph. Despite a generally mediocre year, Bartoli's victory in tennis' biggest event cannot be dismissed.
ATP Ranking: 4
2013 Match Record: 26-15
2013 Grand Slam Results: Australian Open semifinals; French Open runner-up; Wimbledon quarterfinals; U.S. Open quarterfinals
Assessment: David Ferrer held a career-high No. 3 ranking for five weeks this summer, a testament to his consistency. He got to the final of a Grand Slam event for the first time, losing to Rafael Nadal in the 2013 French Open. His quarterfinal berth in the U.S. Open represented the eighth straight major in which he reached at least the quarterfinals.
However, Ferrer lacks big wins in 2013. He has won two tournaments this year, but none since February, and he has a 1-8 record against Top 10 players this year. Ferrer, 31, consistently beats the players he should beat, but does not have the weapons to beat the elite players.
WTA Ranking: 3
2013 Match Record: 37-7
2013 Grand Slam Results: Australian Open semifinals; French Open runner-up; Wimbledon second round: U.S. Open did not participate
Assessment: Maria Sharapova had an outstanding first half of 2013, getting to the final in five of the first seven tournaments she completed, winning two of them. She was a finalist at the French Open, and, at that point, four of her five 2013 losses were to Serena Williams.
Things went sour after that, though. She lost to qualifier Michelle Larcher De Brito in the second round at Wimbledon and lost to Sloane Stephens in her only subsequent match before she withdrew from the U.S. Open with a shoulder injury.
ATP Ranking: 3
2013 Match Record: 41-8
2013 Grand Slam Results: Australian Open runner-up; French Open did not participate; Wimbledon champion; U.S. Open quarterfinals
Assessment: Andy Murray had reached the final of the last four Grand Slam events he had entered before losing to Stanislas Wawrinka in straight sets in the U.S. Open quarterfinals. A letdown was predictable after all the attention he received in Great Britain for being the first British male in 77 years to win Wimbledon.
However, that lopsided loss to Wawrinka, coupled with disappointing performances in the two hard-court tune-up events preceding the Open, spoiled what had been an outstanding year.
He is 5-5 against Top 10 players this year and split his two matches against Novak Djokovic. Murray has yet to face Rafael Nadal in 2013. Murray probably benefited from missing the French Open, where he has never reached the final and was a semifinalist only once. Winning Wimbledon for the first time in his career remains a milestone accomplishment, however.
ATP Ranking: 1
2013 Match Record: 50-9
2013 Grand Slam Results: Australian Open champion; French Open semifinals; Wimbledon runner-up; U.S. Open runner-up
Assessment: It's difficult to say Novak Djokovic has had a disappointing season, given his impressive Grand Slam results. But with the remarkably high standard Djokovic has set for himself, his 2013 performance might be considered a bit of a letdown.
He is the only player, male or female, who reached at least the semifinals of all four majors in 2013, and he is the only player who got to the final in three of them. He also won a Grand Slam title for the third straight year and has reached the semifinals of 14 consecutive Grand Slam events. Plus, he has been ranked No. 1 every day of 2013.
However, Djokovic has not won any of his past seven tournaments, and he has only three tournament titles in 2013 after winning 16 over the previous two years. He is 1-1 this year against Andy Murray and 1-3 against Rafael Nadal, who is likely to take the No. 1 ranking away from Djokovic by year's end.
WTA Ranking: 2
2013 Match Record: 42-5
2013 Grand Slam Results: Australian Open champion; French Open semifinals; Wimbledon second round (withdrawal); U.S. Open runner-up
Assessment: Excluding the three tournaments in which she had to withdraw because of injury, Victoria Azarenka got to the final of six of her eight tournaments in 2013 and won three of them.
She got at least to the semifinals in all three Grand Slam events she completed, and her victory in the Australian Open was her second major title. Azarenka has an 8-3 record against players ranked in the Top 10 in 2013, including a 2-2 mark against Serena Williams.
The 24-year-old Azarenka has yet to win a Grand Slam title other than the Australian Open, and she has slipped one spot from the No. 1 ranking she held when the year began.
However, her 42-5 match record typically would be good enough to keep the No. 1 ranking. Azarenka is clearly the second-best female player in the world at the moment, and there is a gap between the top two and the rest of women's tennis.
WTA Ranking: 1
2013 Match Record: 67-4
2013 Grand Slam Results: Australian Open quarterfinals; French Open champion; Wimbledon fourth round; U.S. Open champion
Assessment: This is shaping up as Serena Williams' best year since 2002, when she won all three Grand Slam tournaments she entered and finished the year ranked No. 1 for the first time. Surprisingly, she has finished the year No. 1 only one other time (2009), but, barring a major collapse, she will do it again in 2013.
Her victory in the U.S. Open represented her 17th Grand Slam title, leaving her one behind Chris Evert and Martina Navratilova and seven behind all-time leader Margaret Court. Williams' two Grand Slam victories this year give her titles in four of the past six majors as she approaches her 32nd birthday.
She has won nine of the 14 events she has played this year and has an 11-2 record against players ranked in the Top Five. The only negatives in 2013 are the fourth-round loss to No. 23-ranked Sabine Lusicki at Wimbledon and her 2-2 record against No. 2-ranked Victoria Azarenka.
ATP Ranking: 2
2013 Match Record: 60-3
2013 Grand Slam Results: Australian Open did not participate; French Open champion; Wimbledon first round; U.S. Open champion
Assessment: Were it not for the inexplicable first-round loss to Steve Darcis at Wimbledon, Rafael Nadal would be enjoying one of the greatest seasons in men's tennis history. Nadal has won 10 of the 12 tournaments he has played since his February loss to Horacio Zeballos in Nadal's first tournament in seven months.
Nadal's only losses since then have been to Novak Djokovic in the final in Monte Carlo and that straight-sets loss to Darcis, who was ranked 135th at the time and has since dropped to No. 165.
Certainly, Nadal's knee problems contributed to that upset, but that does not fully account for the magnitude of the loss in the context of his 2013 results. Wimbledon is the only tournament this year in which Nadal did not reach the final.
Nadal won two of the three Grand Slam events he entered this year, including a record eighth French Open title. His 13 titles in majors is four shy of Roger Federer's record, and, at age 27, Nadal is capable of catching Federer. Nadal is 3-1 against Djokovic this year and has not faced Andy Murray. Nadal probably will be ranked No. 1 at year's end.