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 the friends 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.''
Nishikori was successful on only 43 percent of his first serves. He says he is still returning to form after an abdominal strain 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.''
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.''
Earlier Friday, Gilles Muller of Luxembourg defeated Matthew Ebden of Australia 6-4, 6-4.
No. 1 seed John Isner is scheduled to play Jack Sock and No. 4 seed Andy Roddick is set to play Michael Russell later Friday night.