Iga Swiatek moved into the quarter-final at the French Open on Monday after a nervy three-set win over the unseeded teenager Qinwen Zheng.
It was her 32nd consecutive triumph on the senior circuit. But it was far from the usual romp.
After warding off two break points in her opening service game, Swiatek captured Zheng's serve and held to go 3-0 up within 15 minutes.
But the 19-year-old was soon on the board. A slick serve and volley combination to clinch the fourth game highlighted her growing confidence.
She outslugged Swiatek in a 20-stroke rally to bring up a break point and after some more brutal hitting, Zheng claimed the Pole's service.
But she could not maintain the form and allowed Swiatek to pull clear at 4-2.
Crack
However, Swiatek cracked from a position of ascendance.
Two consecutive set points were squandered and a third was wasted with her first double fault of the encounter.
The 20-yeaer-old subsequently lost the game and Zheng held quickly to level at 5-5 after 54 minutes.
Swiatek's woes continued. She dug herself out of a hole in her next service game. She had to come back from 15-40 to nudge ahead 6-5. And then failed to take advantage of two separate set points on Zheng's service.
The subsequent tiebreak epitomised Swiatek's first set travails. She dropped the first two points, won five on the trot and then lost the same number to cede the set.
Luck
But then her luck turned, Zheng called for the physio at the start of the second set.
And Swiatek swept through the next eight games to level the match and notch up the break in the decider.
Zheng, playing in the senior tournament for the first time, got back on the board and twice threatened the Swiatek serve to level at 2-2 but Swiatek just about held on for 3-1.
Another two break points went begging as Zheng refused to yield. A more convincing service game took the top seed to 4-2.
She carved open the point for a double break following a forehand winner down the line to end a 22-stroke rally of punishing groundstrokes.
End
Swiatek wrapped it up with the panache that had eluded her for much of the two hour and 45 minute encounter.
"She's been playing amazing tennis," said Swiatek of her adversary. "I'm pretty happy that I could come back after a pretty frustrating set."
Swiatek will take on the 11th seed Jessica Pegula in the last eight after she came from a set down to beat the unseeded Romanian Irina-Camelia Begu 4-6, 6-2, 6-3.
The pair played in the semis on the hard courts at the Miami Open in March.
The last eight will be their first meeting on clay. "Jessica is a dangerous opponent," said Swiatek of the 28-year-old American.
"The quarter-final is a stressful round but hopefully if I'm focused and play my tennis I should be OK."
