Canada's Eugenie Bouchard bowed out of the US$2.4 million women's Rogers Cup, falling 3-6, 6-4, 6-3 to qualifier Kristina Kucova in a third round match she looked to let slip away after an impressive opening set.
The gritty Kucova, who upset eighth-seeded Carla Suarez-Navarro in the second round, advanced to a quarter-final Friday night against 15th seeded Johanna Konta of Britain.
The match included a ball batted high into the crowd in frustration in the second set to a point penalty for racquet abuse in the third as Bouchard struggled to hit the lines to the disappointment of what had been a festive centre court crowd at Uniprix Stadium.
Bouchard, who had not looked so sharp of late since her breakout 2014 season when she reached the Wimbledon final, shot out to a 4-0 lead in the opening set. But then nerves showed as she missed the lines on a handful of what could have been easy winners before putting the set away.
The 22-year-old broke service for a 3-2 lead in the second only to see her own service go south as she was broken three times. She lost the final eight points of the set.
Bouchard, who beat Kucova in a Federation Cup match in their only previous meeting in 2014, looked rattled in the third as unforced errors ended rally after rally until she finally hit long on match point and Kucova let out a shriek in victory.
Konta needed just one hour seven minutes to dispatch Varvara Lepchenko 6-3, 6-2. The 25-year-old Konta has been on the rise in the last three seasons and won her first WTA tournament last week in Stanford, Calif., when she defeated Venus Williams in the final.
Anastasia Pavlyuchenkova survived a second-set scare to upset fourth-seeded Agnieszka Radwanska
Pavlyuchenkova, seeded 16th, let two match points slip away while leading 5-4 in the second set and then lost the game on a double fault. But she rebounded in the third to extend her longest run ever at the hardcourt event.
"I think I'm still recovering from the second set," she said in a courtside interview. "Basically, I thought I had the match in my pocket and lost it, so I'm happy with the mental side."
Angelique Kerber, the second seed from Germany, bounced back to beat Elina Svitlolina of Ukraine 1-6, 7-6 (2), 6-4 to advance to a quarter-final meeting with 19-year-old Russian Daria Kasatkina, a 7-5, 6-3 winner over Italian Roberta Vinci.
An all-American battle saw Madison Keys breeze by 36-year-old Venus Williams 6-1, 6-7 (2), 6-3 in one hour 50 minutes. Keys will face Pavlyuchenkova on Friday.
The 10th-seeded Keys was all over a listless Williams, taking seven straight games before her sixth-seeded opponent held serve for 2-1 in the second set. She held again and won four in a row as Keys started spraying the ball and wasting easy points and took the set on a one-sided tiebreaker.
Keys found her serve in the third, punctuating the win with an ace on match point, to reach her first Rogers Cup quarter-final.
Williams has appeared at the tournament seven times. She lost in the first round five times and won one match this time, but in 2014 she reached the final, losing to Radwanska.
Fifth-seeded Simona Halep, a finalist last year in Toronto, bulled past 14th seeded Karolina Pliskova of the Czech Republic 6-3, 6-3.
The 24-year Romanian will next face Svetlana Kuznetsova, the ninth seed who downed 12th seeded Czech Petra Kvitova 7-6 (2), 6-3.
Halep was up against the WTA Tour leader in aces with 360, although Pliskova managed only five in the match.
"I knew that it's going to be tough because I don't get rhythm from her," said Halep. "You never know what to expect for the next point, so there's a bit of tension.
"I just had to stay patient for every ball and to keep fighting because I knew that if I stay there for every ball, she can miss more than me."
Not a big hitter herself, Halep made up for it by landing 72 per cent of her first serves.
"I am improving a lot," she said. "Now I already got the rhythm a little bit, the timing.
"I don't serve very strong, but it's better that I can put the first serve more into the court. My percentage is higher than normally."