James Blake blew his gold medal chance in the men's singles on Friday, then accused Chile's Fernando Gonzalez of trampling over the Olympic ideals.
Gonzalez set up a men's singles final against Spain's Rafael Nadal, saving three match points on his way to a 4-6, 7-5, 11-9 victory, but promptly came under fire from the angry American.
There was no bad blood to spice second seed Nadal's late night blockbuster with Serbia's Novak Djokovic. The two warriors produced a semi-final of rare quality which Nadal took 6-4, 1-6, 6-4 when his weary opponent blazed an easy smash out.
Blake's remarks cast a black mark over another dramatic night at the Olympic Tennis Centre which also saw Swiss Roger Federer reach the men's doubles final with Stanislas Wawrinka.
The 28-year-old's grievance stemmed from an incident when he led 9-8 in the decider. He hit a forehand just over the baseline but was convinced the ball had shaved Gonzalez's racket frame as the Chilean took evasive action.
Television replays seemed to suggest he was correct.
"Playing in the Olympics, in what's supposed to be considered a gentleman's sport, that's a time to call it on yourself," Blake told reporters.
"Fernando looked me square in the eye and didn't call it. Maybe I shouldn't expect people to hold themselves to high standards of sportsmanship. But yes, I did expect it a little more so in the Olympics."
GOLD MEDAL
The row took the gloss off Gonzalez achievement. He can now add another gold medal to the one he pocketed with Nicolas Massu in the doubles in Athens four years ago.
"I mean there is an umpire. It was love all, 8-9," Gonzalez said when grilled by reporters who asked him virtually nothing about his victory.
"I was really tired. I didn't feel anything. If I'm 100 percent sure about it, I will give it."
Sandwiched in between the men's semi-finals, women's world number one Jelena Jankovic lost her delayed singles quarter-final against in-form Russian Dinara Safina.
Safina, playing at her first Olympics, won 6-2, 5-7, 6-3 to join fellow Russians Elena Dementieva and Vera Zvonareva in the last four. She will face China's Ni La.
Federer, upset by Blake in singles on Thursday, has the chance of a first Olympic gold medal on Saturday with Wawrinka after beating Americans Bob and Mike Bryan 7-6 6-4.
The other semi produced extraordinary scenes when Swedes Simon Aspelin and Thomas Johansson beat Frenchman Arnaud Clement and Michael Llodra 7-6, 4-6, 19-17 -- the longest three-set men's match since tennis returned to the Games in 1988.
In the women's doubles, Serena and Venus Williams put aside their singles setbacks to reach the semi-final with a 6-4, 6-0 defeat of Russians Zvonareva and Elena Vesnina, but fellow Americans Lindsay Davenport and Liezel Huber bowed out to Spain's Anabel Garrigues Medina and Virginia Ruano Pascual.
Chinese pair Yan Zi and Zheng Jie staged a remarkable late show, beating Russians Svetlana Kuznetsova and Dinara Safina 6-3, 5-7, 10-8 to reach the last four in a match that stretched to 3.30 a.m. on Saturday.
