Alexander Zverev saw off Lorenzo Sonego 6-4, 6-3 with a decisive ace at the China Open on Friday as Coco Gauff launched her bid for a repeat crown.
World No 3 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 that is tricky for me. We had long matches, tough battles in the past but I'm happy to be through, definitely."
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 into the right way," he said. "That's what I'm trying to do again, step by step, now."
The 29-year-old former world No 1 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 No 2 Sinner will face qualifier Terence Atmane of France.
FAMILIAR GROUND
In the women's draw, 21-year-old Gauff brushed aside Russia's Kamilla Rakhimova 6-4, 6-0 to secure a spot in the last 32.
"I think the mindset is a little bit different just because when you play well at a place, you have a lot of confidence," Gauff said after the match.
"When those tough moments happen, you feel the familiarity of the conditions from the years before that," she said.
The defending Beijing champion powered through a few drawn-out games to take down the 89th-ranked Russian in her first appearance since the US Open.
An energised Gauff broke early in the second set and worked hard to save break points over the frustrated but defiant 24-year-old Rakhimova to close out the match without trouble.
"I expected it to be close," Gauff told reporters.
"She's a great player, and she's had competitive results with top players in the last few tournaments.
"I just found my rhythm and got in the flow."
The world No 3 from the United States will next face Canada's Leylah Fernandez, who triumphed 6-2, 6-0 over Greece's Maria Sakkari.
Also into the next round is fellow American Amanda Anisimova, a US Open finalist, beating Britain's Katie Boulter 6-1, 6-3.
The 24-year-old world No 4 next plays home favourite Zhang Shuai – who last year in Beijing snapped a more than 600-day winless singles streak as then-world no. 595.