Dominic Thiem withstood 30 aces from big-serving Canadian Milos Raonic to win 7-6 (5), 5-7, 6-4 on Wednesday and reach the third round of the Paris Masters.
The two-time French Open runner-up also saved nine break points out of 10, and then broke Raonic for the first time in the ninth game of the deciding set before serving out the match.
The fifth-seeded Austrian player, who won the Erste Bank Open in Vienna last Sunday for an ATP Tour-leading fifth title this year, next faces Grigor Dimitrov.
Seventh-seeded Stefanos Tsitsipas looked more comfortable reaching the third round, serving 13 aces and facing no break points in beating Taylor Fritz 7-6 (3), 6-3. The 21-year-old Greek player next plays Alex de Minaur, a 20-year-old Australian who lost the Swiss Indoors final to Roger Federer on Sunday.
Federer is skipping this tournament, but top-ranked Novak Djokovic and No. 2 Rafael Nadal were playing later Wednesday in the second round.