ROGER FEDERER feared for his French Open existence during his testing secondround win over Argentina’s Jose Acasuso yesterday.

The second seed ended up clinching a 7-6 (10/8) 5-7 7-6 (7/2) 6-2 victory over the world number 45, but could easily have lost the first three sets.

He saved four set points in the first-set tie-break and another one midway through the third set, during which he really lost his way.

The Swiss came through smiling, though, showing decent form in the fourth set, but acknowledged it could have been a different story.

“Yes, we both could have won the first three sets,” he said. “I’m thrilled to have got through such a tough match.

“Coming through a tough match like this is always a great feeling. I’m not part of such close matches that often so when they happen, it’s great to put in the fight when you can.”

There were worrying signs for Federer, bidding to claim the only major title to so far elude him, in a first set which lasted 66 minutes.

He was broken midway through it and then fell 6-3 down in the tie-break. He went on to save four set points before turning things around.

After losing the second set, the 26-year-old Acasuso, who has won just two matches since the end of February, capitalised on a host of errors by the world number two to break twice early on in the third, going 4-0 then 5-1 ahead.

To his credit, Federer managed to stay calm when all around him were reaching for the record books to find out when he last went out this early in a grand slam.

That was in 2003, also at Roland Garros when he crashed out in the first round, but in typical Federer style he came storming back.

He saved a set point when Acasuso was serving at 5-2 up and, after winning five games on the bounce, he had no problems claiming the tie-break as the Argentinian started to lose hope.

The fourth set was a formality and Federer, who won 12 of the last 15 games, felt his superior mental strength got him through some sticky moments.

Fifth seed Juan Martin del Potro’s progress into round three, a stage he has never reached before at Roland Garros, was much more serene.

He eased past Viktor Troicki 6-3 7-5 6-0 and will next play Russia’s Igor Andreev, the 25th seed.