World number one and top seed Angelique Kerber saw off determined Czech player Barbora Strycova 6-3 7-6 (7/4) to reach the third round of the China Open in Beijing.
The German, winner of both the 2016 Australian Open and US Open titles while runner-up at Wimbledon, took the opening set in 38 minutes with two breaks.
However, she then failed to hold her own serve four times as Strycova, the world number 21, forced a tie-break.
Kerber, though, recovered to take her first match-point chance and secure victory in one hour and 36 minutes.
She will next face Elina Svitolina for a place in the quarter-finals after the Ukrainian 16th seed defeated German wild card Sabine Lisicki 6-4 6-4.
In Wednesday's evening session, Petra Kvitova knocked out second seed and tournament holder Garbine Muguruza with a 6-1 6-4 victory.
The 14th seeded Czech, who came into the contest on a seven-match winning streak, will next Madison Keys after the American saw off Russia's Svetlana Kuznetsova 7-6 (7/2) 6-2.
Fifth seed Karolina Pliskova came from behind to beat Russian Daria Kasatkina 3-6 7-5 7-6 (9/7).
Czech Pliskova will play Johanna Konta in round three after the British number one, seeded 11, saw off Timea Babos of Hungary 7-5 6-2 in their match which was held over from Tuesday because of rain.
China wild card Shuai Peng was beaten in three sets as Caroline Garcia of France progressed 6-3 3-6 7-6 (7/4), while Australian Daria Gavrilova knocked out 12th seed Timea Bacsinszky, defeating the Swiss player 4-6 6-0 6-4.
Source: PA
