ATLANTA -- Go Soeda upset Olympics doubles partner Kei Nishikori 6-2, 6-1 Friday in the quarterfinals of the Atlanta Open.
The match was the first pairing of two players from Japan in an ATP quarterfinal since the Open era began in 1968. Each also will represent Japan in singles in the London Olympics.
Soeda said Friday's draw was difficult for him but perhaps more difficult for Nishikori, Atlanta's No. 3 seed who is ranked 19th in the world. Soeda is ranked No. 54.
"Actually I don't want to beat Kei because we are good friends," Soeda said. "This is tough to have to play. I think he was more nervous. I was nervous, too, but his ranking is high. I have nothing to lose. I think it is easier to win."
Andy Roddick, the No. 4 seed, beat Michael Russell 6-3, 6-4 Friday night. Top seed John Isner played Jack Sock in Friday night's last quarterfinal.
Earlier Friday, Gilles Muller of Luxembourg defeated Matthew Ebden of Australia 6-4, 6-4. Muller will play Soeda and Roddick will play the Isner-Sock winner in today's semis.
Nishikori won only 43 percent of his first serves. He says he is still returning to form from a left oblique injury.
"I was injured before Wimbledon," Nishikori said. "I guess I didn't get my confidence yet."
Nishikori didn't blame the loss on nerves or the fact he was playing against his doubles partner and friend.
"I didn't feel much pressure," Nishikori said. "I just didn't play well, I think.
"I couldn't put in the ball, especially my backhand and my serve."
The match was the first between the friends in an ATP event.
Nishikori said Soeda "played unbelievably good."
"He didn't miss and he was really aggressive," Nishikori said. "At the same time I didn't play well. I couldn't put in the ball somehow. I lose my confidence."
Russell, 34, was the oldest player in the field.
Roddick broke Russell's serve to go up 5-3 in the first set. The second set was even at 4-4 when Roddick broke Russell's serve again.
Those were the only two breaks of the match.
Roddick won 86 percent of his first serves and faced only one break point. He had 12 aces.
"If I could take the serving stats from today and apply them to any match, I would sign up right now," Roddick said.