The former world number one advanced to the third round after a titanic tussle with the left-handed Spaniard and triumphed in three tie-breaker sets 7-6 (15-13) 6-7 (1-7) 7-6 (9-7) just short of three hours.

Lopez was buoyed by a patriotic crowd on the Manalo Santana stadium in Madrid including fellow Spanish player Fernando Verdasco and produced tennis worthy of the occasion.

At 5-2 up in the final set tie-break Lopez missed an easy overhead smash much to the disbelief of the crowd that would have given him match point. From then on Federer battled back into contention and was able to push on for victory, saving a match point in the process.

In his post match interview Lopez was aware of the importance of the crucial overhead miss: "Maybe that was the key because if not, I would have been up 6-2 and I´d have had the match in my hand but it was a really high ball and I couldn’t see it and with the conditions on the court it wasn’t really clear for me but the ball went three meters out and because I couldn’t see the ball," Lopez said in his post-match press conference.

"Obviously if I had won that point it would have been very complicated for him because I would have had four match points and I think there were other moments." he continued. "I think that today on the big points, he played really good. I have probably only made one error, that ball we were talking about."

Swiss Federer was relieved to have made it through to the third round.

"I could have lost, so I'm obviously relieved to have come through this one," Federer said in an on-court interview after winning. "It was a tough match and a nail biter really from start to finish, so it's nice to play those sorts of matches."