Charleston - Sixth-seeded Eugenie Bouchard notched one of the biggest wins of her career on Friday, reaching the semi-finals of the WTA Family Circle Cup by toppling world number eight Jelena Jankovic.
The 20-year-old Canadian outlasted former world No 1 Jankovic 6-3, 4-6, 6-3 in a rematch from last year's quarter-finals at this green claycourt event.
Jankovic won that one, but has now lost two out of three matches against rising star Bouchard.
"I knew in the second set my game wasn't where I wanted it to be," Bouchard said.
"I think she did a good job of stepping in and controlling ... I was really on the run. And that's fine, but that's not where I want to be most of the time. I needed to get back to my game."
Bouchard will next face fourteenth-seeded Andrea Petkovic, who surprised ninth-seeded Lucie Safarova in another three-setter 6-3, 1-6, 6-1.
Bouchard put on a dazzling display of foot movement and precision returns to throw Jankovic off her game.
She blasted two aces and won 65 percent of her first-serve points in the two hour and two minute match at the claycourt tournament.
"She's very solid," said Jankovic of Bouchard. "She stays so low and takes your balls so early off the ground, so even if you hit hard, she just picks them up so easily and kind of directs them.
"That's her biggest strength, that she can absorb someone's ball and just use it."
This is Bouchard's second semi-final of the year after reaching the semis of the Australian Open.
Bouchard has three wins over top 10 players prior to this but never a number eight. She beat number nine Samantha Stosur in Charleston last year, then-10th-ranked Jankovic in Japan last year and earlier this year she upset number 10 Sara Errani in Indian Wells.
Bouchard has shot up the rankings in the past year. The world number 20 was ranked 114th when she lost at this event to Jankovic in 2013.
Jankovic rallied in the second set after Bouchard broke the Serb to take a 4-3 lead. Jankovic then won four straight games to force a third set.
"I didn't really think about how I was up a break in the second, because it was in the past, and I had to move forward," Bouchard said.
Jankovic, who won this event in 2007, had one double fault and won just seven of 19 points on her second serve.
"I started well, but then I dropped a level, and I felt a little bit flat, especially after 3-3 in the first set," Jankovic said. "I lost a couple of games in a row and let her take control of the match."
Bouchard advanced to the quarter-finals by beating former world number one Venus Williams 7-6 (8/6), 2-6, 6-4.
Results on Friday from the WTA Tour Family Circle Cup (x denotes seeded player):
Jana Cepelova (SVK) bt Daniela Hantuchova (SVK x12) 6-2, 6-1
Belinda Bencic (SUI) bt Sara Errani (ITA x3) 4-6, 6-2, 6-1
Eugenie Bouchard (CAN x6) bt Jelena Jankovic (SRB x2) 6-3, 4-6, 6-3
Andrea Petkovic (GER x14) bt Lucie Safarova (CZE x9) 6-3, 1-6, 6-1