Why He Won
His ability to hit big shots. Federer struggled in losing the second set, but he was able to recover and hit the big shots when he needed to. He won a higher percentage of points than Mahut on his first serve (82 percent to 63), second serve (66 to 48) and while receiving (42 to 25). He also hit 54 winners to just 25 for Mahut.
The Fed Express will face Belgian qualifier David Goffin in the fourth round. He has yet to face a seeded player. Goffin is the first lucky loser (a player who did not make it through qualifying, but was inserted into the draw because of a withdrawal, in this case Gael Monfils) to make it to the fourth round of the French Open.
This is the furthest a lucky loser has advanced in any Grand Slam since Dick Norman made it to the fourth round at Wimbledon in 1995.
Federer has made it to the fourth round without having to face a seeded player. Assuming he wins, Federer will face the winner of the fourth-round match between Juan Martin del Potro and Tomas Berdych.