British number two Kyle Edmund was beaten in straight sets by second seed Alexander Zverev in the first round of the China Open in Beijing.
Edmund, ranked 47th in the world, had the chance to serve for the second set but Zverev broke to force a tie-break.
The German went on to win 6-3 7-6 (7-3) and set up a second-round meeting with Italy's Fabio Fognini.
Earlier, world number one Rafael Nadal saved two match points as he came from a set down to beat Lucas Pouille.
Edmund, 22, was playing in his third match since he suffered a neck injuryduring the US Open in September.
He won the first five points of the match against Zverev, but an early break allowed the world number four to take the set, before a composed tie-break performance ensured victory.
Nadal, making his first appearance since last month's US Open win, was 4-6 down in the second set tie-break before winning four consecutive points.
The Spaniard, 31, then converted his only break point of the match in the final set to beat the French player 4-6 7-6 (8-6) 7-5.
"I am very, very happy to be through," said Nadal.
"He played well, I think, very aggressive. He's serving well. For me it was a little bit difficult at the beginning, then I started to play better.
"But still, I didn't have the control of the match for almost all the time."
Nadal, who won his 16th Grand Slam title in New York three weeks ago, goes on to play Russia's Karen Khachanov in the next round.
Elsewhere in Beijing, Australia's Nick Kyrgios beat Georgia's Nikoloz Basilashvili 6-1 6-2, Bulgaria's Grigor Dimitrov beat Bosnia's Damir Dzumhur 6-1 3-6 6-3 and Argentina's Juan Martin del Potro is also through after a 7-6 (7-4) 6-4 win against Pablo Cuevas of Uruguay.
American John Isner reached the second round with a 6-2 6-3 victory over Tunisia's Malek Jaziri, while Czech Tomas Berdych beat American Jared Donaldson 6-3 0-6 6-2.