The Georgian let slip a match point and dropped serve at 5-4 in the second set, then steadied in the tie-break and closed with his ninth ace after one hour and 33 minutes.
“It was a tough moment when I dropped serve at 5-4,” Basilashvili said. “I got slightly tight. My energy level dropped a bit and that was not a great moment. But my serve helped me a lot… I was somehow able to put more energy into points and very happy I could finally execute and win the match.”
He is the fourth qualifier to reach the last four in Chengdu, after Bernard Tomic, Alibek Kachmazov and Alejandro Tabilo. Next he faces second seed Alejandro Davidovich Fokina, who beat French qualifier Alexandre Muller 6-1, 7-5.
Davidovich Fokina has not dropped a set in two matches on his Chengdu debut. He missed the North American hard-court swing through injury and won his first tour title in Mallorca earlier this year.
Denis Shapovalov came from a set down to beat Adrian Mannarino 6-7(6), 6-3, 6-2 in two hours and 34 minutes. It is his second Chengdu semi-final after 2019. He will play fifth seed Hubert Hurkacz or Lloyd Harris, who stunned top seed Valentin Vacherot on Saturday.
Three different paths — a qualifier’s first last-four in four years, a Spaniard returning from injury, and a Canadian rebuilding form — set up the Chengdu semi-finals.