Roger Federer is desperate to add Olympic gold to his 16 grand slam singles titles in London this summer to fill the one gaping hole in his career achievements.

Roger Federer of Switzerland serves to Tobias Kamke of Germany during the French Open tennis tournament at the Roland Garros stadium in Paris, May 28, 2012. [Photo/Agencies]

The Swiss legend won a gold in doubles in Beijing in 2008, but has never been on the top of the medals podium in singles despite lingering frustration at knowing he should have been involved at least once.

"It's different pressure because the form is best of three so you feel like you have a bad five minutes and that could be it. That's kind of what cost me against (Tomas) Berdych in Athens, against (James) Blake in Beijing," said Federer.

"And then next thing, you know, you're out of both tournaments, and I think I was seeded 1 or 2 in either one of them."

Federer finished fourth in Sydney in 2000, was knocked out in the second round by Berdych in 2004 and lost a 2008 quarterfinal to Blake.

"Obviously I'm very happy to represent Switzerland. I did way too good back in 2000 (where he finished fourth), didn't do so well in Athens. In Beijing, I was really close to a medal in the singles and then in doubles I got the gold," added Federer, who took the title with Stanislas Wawrinka.

"So I feel very relaxed going into the Olympics. I don't feel like this is a must win for me or anything like that. I probably would feel a bit more pressure if I wouldn't have won Olympic gold in doubles in Beijing."

Federer, who is likely to set the new grand slam match record in the next round where he faces Romania's Adrian Ungur, now has his sights on another Connors record.

"He had 109 career victories, I'm at 74 now. Is it possible for me to equal Connors' titles? 110, that would be a round figure. That would be incredible. But that's a dream. I go year after year, and we'll see."

Despite Connors' standing in the sport, Federer said his relationship with the great American has not always been close.

"He didn't talk to me much when he was working with Andy Roddick. He was quite distant at that time, which is a bit weird, because I got on very well with Roddick," explained Federer. "But I think he respects me very much. He is much closer to Nadal than to me. Maybe that's the reason."