PARIS May 28 (Reuters) - Roger Federer was kept on his toes before he eventually subdued Argentine journeyman Diego Sebastian Schwartzman 6-3 6-4 6-4 to reach the third round of the French Open on Wednesday.
The 17-times grand slam champion from Switzerland, was kept under pressure throughout by the world No. 109, who never gave up and even broke serve in the first set.
"I've always felt he had a little bit of an upper hand from the baseline. I feel he was doing a really good job being aggressive and making good plays," Federer, who next faces Russian Dmitry Tursunov, told a news conference.
"I wish I could have played a bit more freely today overall. But then again, I think it was a solid match.
"I served well. That's always the key to stay solid in your own service games."
It was the kind of match the former world No.1, seeded fourth in Paris, needed to get ready for tougher challenges that lie ahead.
"I was feeling good, but then I don't know what the reason is but I couldn't really play freely," the 2009 champion said.
"But also, it's good to play this way, as if each point was a break point, because you have to put more energy into your game.
"But then this being said, it's nice to go through difficult moments. Today was such a match even though you can't see this in the score."
Federer admitted he had never seen his opponent before stepping on to court Suzanne Lenglen, but it will be another story against Tursunov.
He has a 4-0 record against the Russian but the two have never played on clay.
Their last meeting was in the third round at Indian Wells, with Federer needing two tiebreaks to go through.
"I think before the match you have to think you're going to play as if it was a hard court," he said.
"You have to slide, if you can, you have to run after the points. But I don't know which points he's going to focus on. Is it semi-volleys? It's difficult on clay sometimes the way the balls bounce.
"But at Indian Wells he played from the baseline. So we'll see. I'll see how I can change the rallies. But also after how I can place my game, if I can use the expression." (Reporting by Julien Pretot; Editing by Pritha Sarkar)