The Czech Republic's Tomas Berdych caused the upset of the men's singles tennis competition after he beat world number one Roger Federer in three sets.
The Wimbledon champion lost 6-4 5-7 5-7 to the unseeded 18-year-old in the second round match on Tuesday.
Berdych, ranked 74th in the world, will now play Spain's 15th seed Tommy Robredo in the next round.
Second seed Andy Roddick fought back from two match points down to beat Germany's Tommy Haas 4-6 6-3 9-7.
Berdych was ecstatic after his victory.
"It was everything. This guy won Wimbledon and the Australian Open and now you are the player who beats him. Unbelievable."
The Czech said he'd been given an advantage by the fact the match was not played in the main arena.
"It's hard to play these big players on Centre Court because they have more practice there. It's easier on the outside courts where they haven't been practicing or playing."
Federer's miserable day was complete when he and compatriot Yves Allegro lost to Indian fifth seeds Leander Paes and Mahesh Bhupathi in the men's doubles.
Roddick also had a tough time against Haas, finally coming through in the most enthralling game of the men's singles.
The US Open champion said the pressure was different from playing on tour.
"This Olympic tennis thing is a lot different than anything I've encountered. I was pretty nervous out there.
"You're playing for your country. It's a lot easier to accept defeat when it's just on you," said Roddick, who will now face Chile's 16th seed Fernando Gonzalez, who beat Korea's Lee Hyung-taik 7-5 6-2.
Earlier, fifth seed Juan Carlos Ferrero and ninth seed Marat Safin were other big-name casualties.
Ferrero let slip a lead of a set and a break to lose 4-6 7-6 6-4 to American Mardy Fish.
Safin, the former world number one, was beaten 7-6 (7/4) 6-3 by Spaniard Feliciano Lopez, who will next face Frenchman Sebastien Grosjean.