World No 3 Daniil Medvedev booked his place in the China Open men's semifinals with a 6-4, 3-6, 6-1 victory over France's Ugo Humbert in Beijing on Monday.
An error-strewn first set saw a combined five breaks of serve but Medvedev edged ahead in the ninth game and finished it off with an ace.
Both men were more consistent in set two until the Russian, at deuce, hit back-to-back double faults to hand the crucial break to Humbert.
But Medvedev finally tightened up in the decider, notching two quickfire breaks before seeing out the match on his serve.
The 27-year-old will battle it out with either world number 10 Alexander Zverev or Chilean Nicolas Jarry for a place in the final.
Medvedev again attributed the see-saw victory to the match balls, which he has said fluff up too quickly and lead to lengthy rallies.
"It's very slow," he told a post-match press conference.
"(On) any other normal hard court with normal balls, no chance I win the match like this. No chance I would lose my serve so much," he added.
"It's great that I managed to still find, in this tough match, these moments of consistency – which was enough to win."
World No 2 and tournament favourite Carlos Alcaraz is due to play his quarterfinal against Casper Ruud on Monday evening.
Top-ranked men's player Novak Djokovic is not playing the China tournaments this season.
