The 29-year-old Australian saved four of the five break points he faced to claim his first career win over Zverev after losing their only previous meeting six years ago. He also beat seventh-ranked Stefanos Tsitsipas at Indian Wells in March.
“I fought off 0-40 first game and I really got into the match after that,” the 60th-ranked Thompson said. “But I held on, I was playing an unpredictable style of tennis, and I think he didn’t handle it that well in the first set and adapted in the second. But I somehow hung around.”
The other three Australians in action Monday all lost as eighth-seeded Felix Auger-Aliassime defeated Aleksander Vukic 7-6 (3), 6-7 (2), 6-2, while Mackenzie McDonald beat Max Purcell 7-5, 6-4 and Sebastian Ofner outlasted Christopher O’Connell 6-7 (2), 7-6 (5), 7-5.
Tour veteran Vera Zvonareva beat Arianne Hatano 6-1, 6-2 in her opening match of the Jiangxi Open.
The 39-year-old Zvonareva, who made her tour debut in 2000, broke her 166th-ranked opponent’s serve six times as she cruised to victory in 61 minutes. Zvonareva next plays fifth-seeded Zhu Lin or Diana Shnaider.