The sensational shot came at the end of the first set. Federer led the set 5-4 and was up 15-love on his Japanese counterpart. Federer sent over a serve and Nishikori returned. Federer responded with a backhand to the right, which Nishikori sent back.
Federer then went back to his backhand, just kissing the ball with his racquet and sending it over the net by inches. The ball stopped in its tracks and gave Nishikori no time to return.
Federer won the match 6-4, 6-4. He faces Novak Djokovic in the semifinals at 11:30 a.m. on Saturday at the AccorHotels Arena in Paris.
"I thought it was really solid," Federer told the ATP. "I'm very happy. I think I played a good match, particularly served much better in the second set, than maybe in previous matches in the past. I didn't really allow Kei to come into the match and points were kept very short at the end and when you play fast court tennis on an indoor court and you feel uncomfortable, it's hard to stop the bleeding sometimes with your opponent."
"I think that was the problem with Kei today."
Karen Khachanov beat Dominic Thiem 6-4, 6-1 in the other semifinal, clinching a spot in the Paris Masters final against either Federer or Djokovic.