World number one Aryna Sabalenka said Tuesday her performances in "key moments" were crucial to surviving a major scare in the China Open second round, after she defeated unseeded Katie Boulter 7-5, 7-6 (7/2) in Beijing.

Sabalenka saved seven break points at 5-5 and then forced the stubborn Briton, ranked 56th in the world, into a rare backhand error to clinch the opening set.

The Belarusian notched another must-win break in the second set to again draw level at 5-5 before triumphing in a tie-break by slamming down an unreturned serve.

She will battle Italy's Jasmine Paolini in the next round for a place in the quarter-finals.

"I think what made the difference was that in the key moments I played a little bit better than her," Sabalenka said at a post-match news conference.

"I think it was all about those last games in each set. She had the opportunity and I'm super glad that I didn't give her those sets easily," she added.

"I kept fighting, kept trying, and that's what made the difference."

World number four Jessica Pegula bounced back from a set down on Tuesday to beat Russia's Anna Blinkova 6-7 (2/7), 6-2, 6-1.

France's world number 10 Caroline Garcia suffered a second-set wobble before downing Kazakhstan's Yulia Putintseva 6-3, 3-6, 6-3.

The women's draw continued through Tuesday with US Open champion Coco Gauff taking on Petra Martic of Croatia for a place in round three.

World number two Iga Swiatek was also in action against France's Varvara Gracheva.

The China Open is taking place for the first time since 2019 after Beijing ditched its isolationist zero-Covid policy.