Aryna Sabalenka came back from 2-5 down in the third set to defeat American teenager Coco Gauff and reach the Ostrava WTA quarter-finals on Thursday.
The big-hitting Sabalenka, the world number 12, took two hours and 13 minutes to beat 55th-ranked Gauff 1-6, 7-5, 7-6 (7/2).
The third-seeded Belarusian got off to a slow start against the patient Gauff who had few problems taking the first set.
Sabalenka won the second 7-5 after breaking Gauff's serve for the first time, but then she started piling up the errors again to see the 16-year-old go 5-2 up in the decider.
A racquet-smashing interlude helped her regain her composure.
Sabalenka drew level against the suddenly nervous Gauff and then dominated the third-set tiebreak in style, ending the match with an ace.
"After 5-2 in the third set I didn't care at all about the result," said Sabalenka, who had lost another three-set thriller to Gauff at Lexington in August.
"I just kept saying to myself, focus on this point, focus on this ball, and I kept saying that until the end and it helped me to be in the moment and not care about anything else."
"She's a great player, she's moving really well and it was really tough for me," added Sabalenka, who will face Spanish qualifier Sara Sorribes Tormo in the quarter-finals.
Gauff regretted her lack of patience in the decisive phase of the match but said she was proud of her performance.
"I think I need to play a little bit smarter on pressure points," said Gauff.
"Sometimes when I get to the end I try to rush out at the point when instead I should just put the ball in the court and make my opponent play."