BASEL, Switzerland — Roger Federer struggled into the Swiss Indoors semi-finals on Friday, the top seed eking out an error-filled 7-6 (7/1), 4-6, 6-4 defeat of Gilles Simon.

Federer has not hit top form all week in Basel and he needed more than two-and-a-half hours to hold off the troublesome French veteran.

“I’m always happy when I win, I’m happy I fought through like this,” Federer said. “There were a lot of breaks, it was all up and down.”

“But I kept my cool and got the job done. I feel good right now.”

The Swiss crowd favorite was never able to comfortably take command against an opponent whom he had defeated in their last six meetings.

It took a fightback in all three sets to come through for a place in a 14th semi-final at the event where he got his start in the game as a ballboy.

The 20-time Grand Slam champion will have to re-group quickly for the semis, where he will play the winner from Greek breakthrough player Stefanos Tsitsipas and Daniil Medvedev.