Andy Murray made a successful return to the ATP Tour as he battled past Tennys Sandgren 6-3 6-7 (6-8) 6-1 in a gruelling contest at the Zhuhai Open.
Murray will now face Australia's Alex de Minaur, who beat countryman John Millman, 6-1 6-3, in 70 minutes.
Murray lost to Sandgren at the Winston-Salem Open in August, before he elected to drop down to Challenger level and compete at the Rafael Nadal Open.
But the former world number one made a strong comeback to the highest tier as he overcame the American in a two-hour 41-minute tussle.
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An exquisite lob handed Murray a double break in set three, finally puncturing Sandgren's resistance as the Scot marched on to secure his first ATP singles win since he beat James Duckworth in January.
Murray had squandered a match point in the set two tie-break - Sandgren taking full advantage to restore parity.
Having not had a single chance of a break throughout set two, Murray took the upper hand when he broke the world number 69 at the first attempt in the final set.
A superb lob shot and a tame Sandgren effort into the net put Murray 4-0 up and the three-time grand slam winner served out a hard-earned triumph.
Qualifier Damir Dzumhur ended a four-match losing streak against Marco Cecchinato, with Zhizhen Zhang defeating Dominik Koepfer to tee up a potential encounter with Nick Kyrgios.
Miomir Kecmanovic progressed past Casper Ruud, who retired hurt, in Tuesday's other encounter.
At the Chengdu Open, Fernando Verdasco eased into round two with a straight sets win over Alexei Popyrin, while top seed John Isner will play Egor Gerasimov.
Dusan Lajovic, meanwhile, will come up against Lloyd Harris, with the duo winning their respective encounters with Juan Ignacio Londero and Marton Fucsovics.