Plenty of action remains at Flushing Meadows, but there has already been several jaw-dropping events from the 2012 U.S. Open.
Let's take a look.
Andy Roddick's Retirement
Roddick is 30 years old. He's won 609 career singles matches and 32 career titles. He's been ranked No. 1 in the world. He won the U.S. Open in 2003 and led the United States to a Davis Cup title in 2007, its first in 12 years.
There's not much else for him to do, especially with his health deteriorating.
It's doubtful that anyone was expecting this future Hall of Famer to play for much longer, but it was still surprising how sudden the announcement was.
Roddick called a press conference on a quiet Thursday night to announce a decision that would completely alter U.S. tennis. Just like that, his next loss would be the last time we would ever see the American compete professionally.
If you saw that coming, you should probably go buy a lottery ticket.
Jo-Wilfried Tsonga's Early Exit
For the most part, it's been a very successful 2012 for the current World No. 6. He won the Qatar Open, he made it to the semifinals at Wimbledon and the quarterfinals at the Olympics and at the French.
However, except for that win at Qatar, the hard courts have not been so nice to the Frenchman. It wasn't going to be a surprise if he failed to mirror his success at the last two majors, but no one was expecting such an atrocious, early exit in New York.
Tsonga matched up with Martin Klizan, the 23-year-old Slovakian with 14 career match wins and zero titles, yet somehow looked completely unmatched in just the second round.
Klizan, ranked No. 52 in the world, won the first set 6-4 with the help of two breaks, but it looked like order was restored when Tsonga took the second, 6-1. Not so fast.
The 23-year-old came back to win the third set, 6-1, in 24 minutes, and the fourth set, 6-3, in 41 minutes, to complete the unexpected dominant win.
Further adding to the surprise, Klizan went on to beat the No. 32 seed, Jeremy Chardy, to advance to Round 4 where he'll look to keep the upsets coming.
What has been the biggest surprise so far?
Caroline Wozniacki Continues Her Plummet
It's a good thing Rory McIlroy continues to bring in the big bucks, because Wozniacki is seriously struggling right now.
After the former No. 1 fell in the third round at the French and in the first round at Wimbledon, the expectations surrounding her were far from sky high. Nonetheless, she's always been a solid hard court player, as she's at least made the quarters in five of her last six majors away from the clay or grass.
However, the No. 8 seed, who had a pretty clear path to Serena Williams in the quarters, failed once again to make it through her first day. In the straight-set loss (2-6, 2-6) to World No. 96 Irina-Camelia Begu, Wozniacki was broken four times, hit just four winners and committed 22 unforced errors.
Wozniacki has been dealing with a right knee injury, but no one was expecting that awful of a showing.