Petra Kvitova had to dig deep to see off the challenge of Serena Williams and progress to the third round of the Cincinnati Masters after an absorbing contest in Ohio.
After suffering the worst defeat of her career to Johanna Konta in San Jose, Williams withdrew from the Rogers Cup for personal reasons, and later revealed she had been struggling with the emotional challenges of balancing motherhood with her career.
The 23-time grand slam singles champion produced an impressive performance in the WTA Premier 5 event, where she is a two-time winner.
But it was not enough to cope with an in-form Kvitova, who emerged a 6-3 2-6 6-3 winner after an entertaining struggle that lasted two hours on the outdoor hard courts of the Lindner Family Tennis Center.
"It's always a pleasure to share a court with her, I'm just happy I did well today," eighth seed Kvitova said.
"She really pushed me a lot, I just tried to stay focused on my serve."
While Williams has returned to the WTA Tour after giving birth last year, Kvitova has endured her own long road to recovery after being attacked with a knife during a break-in at her home in December 2016.
She said: "We all know how tough it is to come back, I couldn't imagine myself being in the top 10. There was a lot of hard work in the rehab and still a lot of things to do."
Kvitova did not take a step back in the opening set, the Czech preventing Williams from settling by dispatching a series of heavy groundstrokes that tested the movement of the returning veteran.
After consolidating a break earned in the fifth game, Kvitova later produced a powerful cross-court forehand from a demanding angle which Williams netted to give up her serve and the set.
It was the turn of Williams to assert herself in the second, the 36-year-old running Kvitova into the ground in a marathon game to take her fifth break-point opportunity, before fending off three in the next game to consolidate.
A second break followed in the seventh game, before Williams served it out to send the match to a third set.
The momentum swung once again in the decider, Kvitova breaking straight back after giving up her serve in the opening game, the 28-year-old rediscovering the movement and aggression that served her so well in the opener.
She secured a second break in the sixth game when Williams sent a backhand down the line long, Kvitova eventually sealing the victory after a pulsating struggle when a backhand serve return attempt from the American sailed long.
Williams opened the tournament in Cincinnati with a first-round win over Daria Gavrilova.
17. November 2018
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|Dybala impressed by Argentina´s improved spirit|
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|NBA wrap: Kyrie Irving sizzles as Celtics beat Raptors in overtime|
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16. November 2018
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|Djokovic makes it three wins from three at ATP Finals|
|Germany relegated from Nations League top tier to cap miserable 2018|
|Fulham will back Ranieri in January transfer window if required|
|Brazil 1 Uruguay 0: Neymar penalty settles tight contest|
|Netherlands 2 France 0: Wijnaldum & Depay decisive as Germany are relegated|
|Wales 1 Denmark 2: Jorgensen and Braithwaite seal Nations League promotion|
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|West Ham´s Zabaleta backs Premier League´s VAR introduction|
|Southgate eyes winning end to England´s ´brilliant year´|
|Patient Zverev seizes opportunity to make amends at ATP Finals|
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|Mahomes hoping to ketchup to Heinz´s touchdown target|
|Ranieri tells Fulham fans not to expect repeat of Leicester ´fairytale´|
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|Croatia star Rakitic ruled out of England clash|
|Capital gains for Zverev as he secures last-four spot in London|
|Sancho rise continues with Player of the Month award|
|Jones-Buchanan, Ablett and Briscoe sign new Rhinos deals|
|Root leads from the front as aggressive England assume control|
|Croatia´s Lovren antagonises Ramos and ´rude´ Spain|
|Rakitic has ´enormous respect´ for England ahead of Nations League decider|
|Ireland make flanker switch with Leavy out of All Blacks clash|
|Pakistan rip through Black Caps in Abu Dhabi|
|WATCH: Barcelona mark 15-year anniversary of Messi´s first match|
|Sterling, that you? - Walker uses falling fan to poke fun at England team-mate|
|Fleetwood applies pressure on Molinari, Wallace leads in Dubai|
|Don´t talk to me about VAR – Rakitic not over World Cup final loss|
|Van Dijk leadership essential for Liverpool – Wijnaldum|
|Dalic: Croatia´s bench was ready to stop Spain!|
|Sublime Root century gives England imposing lead|
|Vinicius appreciates Solari influence at Real Madrid|
|Havertz would suit Bayern Munich – Kimmich|
|Wilder: Roach recruitment a sign of Fury nerves|
|Ranieri targets defensive improvements at failing Fulham|
|PSG close investigation into player recruitment practices after finding no discrimination|
|Mayweather: Nasukawa exhibition back on|
|Witsel: Joining Borussia Dortmund my best career decision|
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|Brazil must make Copa America final – Tite|
|Rockets rout Warriors as Green goes scoreless|
|Seahawks rally past Packers|
|Lakers G Rondo to miss 4-5 weeks|