Roger Federer restored order with his 60th victory at the French Open to reach the third round.

When Federer and Argentina's Diego Sebastian Schwartzman took to Court Suzanne Lenglen, the crowd were still reeling from Serena Williams' shock exit at the hands of Garbine Muguruza.

Coupled with Federer's countryman Stan Wawrinka and his fellow Australian Open champion Li Na both losing in the first round, there was no doubt the tennis world had been rocked significantly off its axis.

Schwartzman, a qualifier playing in the main draw of a grand slam for the first time, hinted at more drama to come when he broke the Federer serve in the third game but the 17-time grand slam champion hit back swiftly to win 6-3 6-4 6-4.

From 2-1 down, Federer won four games in a row and a single break of serve in the second and third sets proved enough, although 21-year-old Schwartzman played a very good match.

In the third round Federer will play 31st seed Dmitry Tursunov, who beat American Sam Querrey 6-4 7-5 6-1.

Federer admitted afterwards he had not felt able to play freely, but attributed that to an unknown opponent rather than any lingering tension from all the upsets.

He said: "It was kind of tough all the way through. I didn't feel relaxed for the entire match. I always felt he had a little bit of an upper hand from the baseline."

Federer is confident his friend and countryman Stan Wawrinka will find the answers to the puzzle he is trying to piece together following his first-round exit.

He said of Wawrinka's difficulties: "It's totally normal.

"I have never really understood how Rafa, Novak, and myself, we can play at such a level all the time. For me, that was a shock to see all of us so consistent like this.

"With Stan, I understand where he is, because I was in such a position at a moment in my career, and it's not even the pressure itself. I think it's how you look at yourself and at your game.

"Without changing everything, this is what he's got to work on and solve this. Little by little. It will not happen overnight.

"But with Australia, with (the Masters title in) Monaco, it's in his pocket already. Nobody can take this from him. It will give him time to work on this. I trust that he will find the right solutions in the months to come."