PARIS — Dominic Thiem beat defending champion Jack Sock 4-6, 6-4, 6-4 to reach the Paris Masters semifinals on Friday.
The Austrian served out the match and clinched victory on his first match point when Sock hit a big forehand long.
Thiem broke the American in the fifth game of the third set, and then showed good composure to save two break points of his own at 15-40 in the eighth game.
Four-time champion Novak Djokovic and Roger Federer, who is seeking a 100th career title, were playing their quarterfinals later Friday.
Djokovic, who is guaranteed to take the No.