The 2012 U.S. Open may be without Rafael Nadal, but that doesn't make it any less exciting. Day 1's action offered a full plate of world-class tennis.
Parity is expected in a tournament without one of its biggest stars, but the first day was mostly without upsets. Small upsets occurred on the men's side of the draw, but nothing substantial shook things up.
The women's side remained completely status quo.
Let's take a look at Day 1's biggest matches and how they finished.
*For full results, click here.
Samantha Stosur defeats Petra Martic
Stosur defeated Serena Williams to win last year's U.S. Open on the women's side, and she got things started the right way this year as well.
She defeated Martic 6-1, 6-1 to advance to the second round of this year's action.
Stosur enters this tournament as the No. 6 seed, but last year's success makes her an interesting candidate to repeat. She's a very good hard court player, and she seems to play her best in front of the U.S. Open crowd.
Andy Murray defeats Alex Bogomolov Jr.
Murray won 6-2, 6-4, 6-1 to advance to the second round. This is a big win for a consistent underachiever.
Murray enters this tournament on an unusual hot streak. He captured a gold medal in the 2012 Summer Olympics, and his straight-set victory on Monday didn't slow him down.
Look for him to continue his success until he reaches the tournament's later stages.
Maria Sharapova defeats Melinda Czink
Sharapova defeated Czink in two 6-2 sets. Her powerful array of groundstrokes simply dominated Czink in her easy victory.
In terms of contenders, Sharapova ranks near the top of the women's ranks. She enters the tournament as the No. 3 seed in the women's draw, and her performance on Monday backed that up.
Sharapova's rocket-like serve will make her a difficult out in the summer's ultimate event.
Roger Federer defeats Donald Young
A 6-3, 6-2, 6-4 win is a solid start for Federer. He defeated a much-lesser opponent, but a win is a win.
Federer was disappointed with his finish in London, but he did win Wimbledon earlier this summer. He's playing very well, and there's no surface he isn't capable of playing on.
Federer's road isn't likely to end until very late in this tournament. His all-around game makes him a tough out on the U.S. Open's hard courts.
Sorana Cirstea defeats Sabine Lisicki
This is a minor upset, but one worth mentioning. No. 16 seed Lisicki lost this one 4-6, 6-2, 6-2.
Lisicki advanced to the U.S. Open's fourth round last year, but she's enjoyed success before. She hasn't performed well this year, but her Wimbledon run last year showed the world that she is a capable performer on the women's side.
Cirstea will try to ride this momentum into the second round. Her athleticism makes her a tough player to play if you can't overpower her.
Victoria Azarenka defeats Alexandra Panova
The women's No. 1 overall seed wasn't expected to lose this match, and she was absolutely dominant in her 6-0, 6-1 win over Panova.
Azarenka, when at her best, is a joy to watch. She has an excellent all-around repertoire, and the Belarus native isn't afraid of the big moment. Because of that, she's the biggest threat to Williams' current reign.
The women's draw is very top heavy, but Azarenka stands out. There's nothing she can't do, and she showed that with her decisive victory over Panova.
Jack Sock defeats Florian Mayer
Mayer was the men's No. 22 seed, so his retirement in the third set could be considered shocking here.
Any upsets at this point in the tournament are worth noting, and Sock scored a reasonably surprising defeat here.
He won 6-3, 6-2 and was winning 3-2 in the third and final set before Mayer called it a day.
In a day with no major upsets, things like this stick out.