Day 4 of U.S. Open action was highlighted by two wild matches on the men's side of the draw. Jo-Wilfried Tsonga was upset by Martin Klizan in four sets, and Mardy Fish battled Nikolay Davydenko for five sets before finally earning the victory.
This is how you know we are getting into the "big" action. Upsets become more commonplace, and the action gets more competitive across the board.
We are almost to the weekend's action, but let's recap Day 4's action first.
Here are some notable results from Thursday's action:
*For complete list of results, click here.
Ana Ivanovic (12) defeated Sofia Arvidsson 6-2, 6-2
Mardy Fish (23) defeated Nikolay Davydenko 4-6, 6-7 (4), 6-2, 6-1, 6-2
Serena Williams (4) defeated Maria Jose Martinez Sanchez 6-2, 6-4
Martin Klizan defeated Jo-Wilfried Tsonga (5) 6-4, 1-6, 6-1, 6-3
Nicolas Almagro (11) defeated Philipp Petzschner 6-3, 5-7, 5-7, 6-4, 6-4
Agnieszka Radwanska (2) defeated Carla Suarez Navarro 4-6, 6-3, 6-0
Marin Cilic (12) defeated Daniel Brands 6-3, 6-2, 5-7, 4-6, 7-5
Tomas Berdych (6) defeated Jurgen Zopp 6-1, 6-4, 6-2
Roger Federer (1) defeated Bjorn Phau 6-2, 6-3, 6-2
Angelique Kerber (6) Venus Williams 6-2, 5-7, 7-5
Tsonga Falls to Klizan in First Major Upset
We hadn't seen an upsets worthy of a gasp yet, but Tsonga's four-set loss to Klizan on Thursday falls under that category.
Tsonga just didn't have his best game today. He lost the first set, but seemed to right the ship with a 1-6 domination in the second set.
He hasn't had success here in the past, but he's still a high seed.
This is a big win for the 23-year-old Klizan. He's never made it this far at Flushing Meadows, and it has to be a thrill for him regardless of what happens next.
Serena Williams Advances
Williams' magical 2012 run continued on Thursday. She defeated Maria Jose Martinez Sanchez in two decisive sets.
So far it seems like Williams hasn't skipped a beat. She's riding momentum from her Wimbledon win and gold medal in London.
She will face Ekaterina Makarova in the third round as she tries to advance to the Round of 16.
Federer Wins Handily
Federer performed exactly as anticipated Thursday evening in his straight-set victory over Phau in Arthur Ashe Stadium.
He will face a stiffer test in his third-round match against No. 25 seed Fernando Verdasco, but FedEx still shouldn't have any issues. He's seeking his sixth career U.S. Open title, and he seems intent on getting there.
Federer's graceful game translates extremely well to hard-court action, and he's playing well. The past few years at Flushing Meadows have not been kind to him, but he looks ready to hoist another trophy.
Fish Wins in Five Sets
Fish and Davydenko played the most competitive match of the day, with Fish coming away with the victory in the end.
After losing the first two sets of the match, the future looked bleak for Fish. But he rallied to win the next three sets in impressive fashion.
Andy Roddick's shocking announcement on Thursday that he will retire after the U.S. Open this year was a blow to American tennis, and Fish almost added insult to injury.
Instead, he will face Gilles Simon in the third round.