Second seed Karen Khachanov saved two match points before defeating unseeded Dutchman Botic Van de Zandschulp 6-7(6) 7-5 6-3 to reach the semifinals of the Great Ocean Road Open in Melbourne on Friday.
Khachanov did not drop serve in his straight-sets victory over Kevin Anderson earlier in the day, but was broken in his opening service game by the world number 159, who had upset American Reilly Opelka in the previous round of the Australian Open warm-up event.
The 24-year-old Russian clawed his way back into the set but Van de Zandschulp held his nerve to clinch a tight tie-break.
The Dutchman had Khachanov on the ropes in the second set and twice came within a point of victory when the Russian was serving to stay in the match at 5-4. But Khachanov battled hard to draw level before breaking and forcing a decider.
The Russian found his range in the third set to book a semifinal date with Italian teenager Jannik Sinner, who beat Serbia's Miomir Kecmanovic in straight sets.
Italian Stefano Travaglia faces Brazil's Thiago Monteiro in the other semifinal on Saturday.
(Reporting by Arvind Sriram in Bengaluru; Editing by Kevin Liffey)
