Things are getting real at the 2014 U.S. Open. We're approaching Round 4, and that means the pretenders have been eliminated.
No one expected No. 3 Petra Kvitova to be a pretender, but after losing in straight sets (6-4, 6-4) to unseeded qualifier Aleksandra Krunic on Saturday, that's exactly what the defending Wimbledon champion is being labeled in the year's final Grand Slam.
A plethora of mistakes led to Kvitova's defeat. She had six double faults and 34 unforced errors. It's going to be hard to win any match with that amount of errors.
Krunic will face Victoria Azarenka next. We'll see if she can continue her improbable run.
Here's a look at the rest of the scores and a recap from Day 6.
No. 1 Serena Williams defeats Varvara Lepchenko 6-3, 6-3
The United States may have just one American remaining in the U.S. Open draw, but it's a very good one. The world's best player continued to look the part on Saturday. Serena Williams took care of a game Varvara Lepchenko in straight sets.
While Lepchenko's effort was strong, she committed 32 unforced errors, and that's no way to beat Williams.
From here, Williams is set to face Kaia Kanepi in the fourth round.
No. 11 Flavia Pennetta defeats Nicole Gibbs 6-4, 6-0
Despite an ineffective first serve, Flavia Pennetta made easy work of a mistake-prone Nicole Gibbs on Saturday. Pennetta only made good on 46 percent of her serves, but 34 unforced errors from Gibbs were more than enough to push Pennetta to the fourth round.
She will face 29th-seeded Casey Dellacqua with a potential meeting with Williams on the line.
Aleksandra Krunic defeats No. 3 Petra Kvitova 6-4, 6-4
Kvitova became the latest high seed to fall. No. 2 Simona Halep and No. 6 Angelique Kerber both went down on Friday.
No. 16 Victoria Azarenka defeats Elena Vesnina 6-1, 6-1
Vika looks to be back to performing at a high level after battling injuries for much of the year.
Azarenka was especially efficient en route to her win. Her first-serve percentage was at 80, and she only committed eight unforced errors.
Azarenka might just be the toughest 16th seed you'll ever see.
No. 7 Eugenie Bouchard defeats Barbora Zahlavova Strycova 6-2, 6-7 (2-7), 6-4
Eugenie Bouchard was made to work, but in the end the young Canadian came away with a hard-fought three-set win over Barbora Zahlavova Strycova.
Strycova took advantage of all three break opportunities during the match but couldn't capitalize on Bouchard's 34 unforced errors.
Though she won on Saturday, Bouchard will need to be sharper in the next round against Ekaterina Makarova.
No. 1 Novak Djokovic defeats Sam Querrey 6-3, 6-3, 6-2
Williams wasn't the only No. 1 seed who validated the rankings on Saturday. Novak Djokovic cruised to an easy win over one of the lone American men left in the draw.
Djokovic seemed to wear Querrey down with his service game as the match went on. His first serve percentage went from 67 to 75 percent and topped out at a dominating 86 in the third and final set.
Next up for Djokovic is No. 22 Paul Kohlschreiber.
No. 8 Andy Murray defeats Andrey Kuznetsov 6-1, 7-5, 4-6, 6-2
Andy Murray probably wasn't expecting such a tough match from Andrey Kuznetsov, but the No. 8 seed had his hands full on Saturday.
After battling to a tough 7-5 win in the second set, Murray dropped the third set before coming back with a controlling 6-2 win in the fourth.
We'll see if Murray can improve when he faces Jo-Wilfried Tsonga in the fourth round. That could be an epic match.
No. 22 Paul Kohlschreiber defeats John Isner 7-6, 4-6, 7-6, 7-6
Kohlschreiber earned the right to face Murray after putting away the last American hope in the men's draw.
For what it's worth, it wasn't an easy win. Isner battled as usual, but he couldn't come up with the clutch points needed to win the match.
Isner leaned on his massive serve as usual to keep it close. He had a remarkable 42 aces in the match, but that was washed away by his 38 unforced errors.
No. 3 Stanislas Wawrinka defeats Blaz Kavcic (Walkover)
A right-foot injury forced Blaz Kavcic out and gave Wawrinka the walkover win. Could this be a good sign for Wawrinka's chances to win the tournament?
Wawrinka's Australian Open run also had the benefit of a walkover, and he played an injured Rafael Nadal in the final. Nadal isn't in the field at all in New York. We'll see if Wawrinka can keep it going next round against the winner of the Nick Kyrgios vs. No. 16 Tommy Robredo.
No. 5 Milos Raonic defeats Victor Estrella Burgos 7-6, 7-6, 7-6
Milos Raonic is knocking on the door of his first finals appearance in a Grand Slam. He reached the quarterfinals at the French Open and the semifinals of Wimbledon earlier in the year.
His opponent on Saturday didn't care much about his solid year and pushed him to the brink in a long three-set battle.
Both men combined for 79 unforced errors, but Raonic's 22 aces were the difference in the match. He'll face No. 10 Kei Nishikori in the next round.
No. 9 Jo-Wilfried Tsonga defeats Pablo Carreno Busta 6-4, 6-4, 6-4
The talented Frenchman took care of business in straight sets. Pablo Carreno Busta had six opportunities to break Tsonga but failed each time.
Tsonga had 14 aces in the match and was the all-around stronger player.
Stats per the U.S. Open official website.