Eugenie Bouchard outlasted Maria Sharapova – the woman she called a «cheat» – in a marathon three-setter to reach round three of the Madrid Open.
Bouchard criticised Sharapova as she made her comeback from a drugs ban at the Stuttgart Open, her only previous tournament after 15 months out.
The Canadian finally came through a brutal encounter 7-5 2-6 6-4 after almost three hours on court.
She will play top seed Angelique Kerber in the third round.
Kerber is set to replace Serena Williams as world number one after reaching the last 16 on the clay of the Spanish capital.
The Bouchard-Sharapova contest was always likely to be fiercely contested after a public exchange of views.
Speaking after Sharapova made her return from a ban for the use of meldonium, Bouchard said: «She’s a cheater and I don’t think a cheater in any sport should be allowed to play again.
«I think from the WTA it sends the wrong message to young kids: cheat and we’ll welcome you back with open arms.
«I don’t think that’s right and she’s not someone I can say I look up to any more.»
When Bouchard’s comments were put to her, Sharapova said that she was «way above» responding.
Though there was no apparent frostiness between them as they entered the court and knocked up, what followed was a fluctuating and full-blooded encounter in which both players refused to give ground.
With breaks exchanged in the first set, Bouchard looked to have blown a huge chance in the 11th game when she missed a forehand into open court with Sharapova stranded.
But the former Wimbledon finalist, now down to number 60 in the world, recovered to take her fourth break point at the end of a 12-minute game and served out to win a first set that last for 70 minutes.
Sharapova, though, found an extra gear in the next stanza, winning four straight games to take the second set as mistakes crept into Bouchard’s game.
The decider was a sapping affair, with each player coming from 0-40 down to avoid being broken – in Sharapova’s case, the Russian did it in successive service games.
A third save from 0-40 was too big an ask for Sharapova, but even then it was not decisive for Bouchard, who surrendered her serve in the next game.
But, from 40-15 up, Sharapova was broken and, in the next game, Bouchard took her second match point for her first victory over the five-time Grand Slam champion at the fifth time of asking.
After two hours and 51 minutes, the players exchanged the briefest of handshakes at the net.
For Bouchard, this represents her biggest win and best run at a tournament since reaching the semi-finals in Sydney in January, while Sharapova still has work to do secure a place in Wimbledon qualifying.