(CNN) -- Maria Sharapova was forced to call on all her resilience to ensure her place in the semifinals of the French Open Tuesday.
The World No.8 endured a nightmare opening set, losing it 6-1 to Spain's Garbine Muguruza, before launching an impressive fightback.
Sharapova, who was beaten in last year's final, won the second set 7-5 before taking the decider 6-1.
The Russian, who won at Roland Garros in 2012, will now face Canada's rising star Eugenie Bouchard.
"I came across a player playing with such confidence and I knew it was going to be a tough match," Sharapova told the WTA website.
"I had a tough start but luckily I had a good finish.
"She was playing so aggressive at the start, but also I wasn't really helping myself with my movement or serving."
Sharapova, seeded seventh, made a dreadful start to the contest and fell 4-0 behind before finally winning a game.
Murguruza, who defeated defending champion Serena Williams 6-2 6-2 earlier in the tournament, played with a verve and quality which belied her age.
After conceding the first set, she slowly got to grips with 21-year-old Muguruza, who was playing in her first ever grand slam quarterfinal.
There was heartbreak for another Spaniard in the other quarterfinal after Carla Suarez Navarro threw away a 4-1 advantage in the final set.
Bouchard, ranked 16th in the world, appeared to be heading out of the tournament but fought back to take the match 7-6 2-6 7-5.
It is a second successive grand slam semifinal for Bouchard, who was beaten in straight sets by Li Na at the Australian Open earlier this year.
"I want to thank everyone here for creating such a great atmosphere," Bouchard said after the match.
"I didn't expect to play such a tough match. She played really well and is a great clay court player.
"At the end of the third set I thought I was getting the upper hand began to believe that I could win.
"I'm just excited to be in the semifinals and to stay a little longer in Paris. I'm just going to enjoy myself in the semifinals."
Meanwhile, Novak Djokovic moved into the semifinals of the men's draw with a straight sets win over Canada's Milos Raonic.
The World No.2, who has never won at Roland Garros, prevailed 7-5 7-6 6-4 to set up a clash with Latvia's Ernests Gulbis.
The Serb will make his 22nd appearance in a grand slam sem-final and his 14th in his last 15 major appearances.
Djokovic is now just two wins away from becoming the eighth man in history to complete the career grand slam.
But standing in his way is the exciting Gulbis, who will compete in his first ever grand slam semifinal.
Gulbis, seeded 18th, overcame Tomas Berdych 6-3 6-2 6-4 to build on his impressive victory over 17- time grand slam winner Roger Federer.
"It's very special," Gulbis said in an on-court interview. "Today was the best match of the tournament. I did everything well."