Alexander Zverev saw off Lorenzo Sonego 6-4, 6-3 with a decisive ace at the China Open on Friday, while Daniil Medvedev also progressed.
World number three Zverev, the second seed in Beijing, next faces France's Corentin Moutet.
The German and Sonego went toe-to-toe for 50 minutes before Zverev converted a break to edge the 30-year-old Italian in the first set after a brief back-and-forth at the net.
A confident Zverev won four straight games in the second for a commanding 5-1 lead.
Although 44th-ranked Sonego held on a little longer, the 28-year-old closed out the match with an ace on his first match point.
"Good start to a tournament," Zverev told Chinese platform Migu Sports after the win.
"(Sonego is) somebody who is tricky for me. We had long matches, tough battles in the past, but I'm happy to be through, definitely."
Medvedev downs Norrie
Also in action at the Beijing ATP 500 event, fan favourite Daniil Medvedev beat Cameron Norrie 6-3, 6-4.
Medvedev hit nine aces for a spot in the last 16, avenging his first-round loss to the Briton at Roland Garros in June.
"There were some moments where I could be better, but I'm happy with the general level of the match," the 18th-ranked Russian told reporters.
He said that while he was still far from his best tennis, he was improving.
"I had dedication, I always have, but maybe I didn't put it in the right way," he said.
"That's what I'm trying to do again, step by step, now."
The 29-year-old former world number one is chasing his first title since 2023 but faces stiff competition in Beijing from Zverev and Italy's Jannik Sinner.
Medvedev next plays Spaniard Alejandro Davidovich Fokina, and world number two Sinner will face qualifier Terence Atmane of France.