INDIAN WELLS, United States (AFP) - Former world number one Garbine Muguruza out-lasted seventh-ranked Kiki Bertens 5-7, 6-1, 6-4 Tuesday (March 12) to reach the WTA quarter-finals at Indian Wells.
Spain's Muguruza, a two-time Grand Slam champion who has slipped to 20th in the world, said mental strength was the key in her 2 hour, 26 minute battle against Bertens.
After an exchange of breaks in the third set, Muguruza finally finished it off with a break of Bertens in the final game, a last bruising rally ending when Bertens spun a backhand wide.
"I don't think it was about the game, it was about staying strong mentally," Muguruza said.
"I never gave up on one point."
Trailing 5-3 in the opening set, Bertens finished off a service hold with three service winners, reeling off four straight games to pocket the set after 71 minutes.
Muguruza had a chance to serve it out at 5-4 but never led in the game, and after Bertens held for 6-5 it was the Spaniard serving to save it. She fended off a pair of break points before smacking a volley into the net on Bertens' third set point.
But after Bertens won the first game of the second set it was all Muguruza as she won six straight games to force the third.
Muguruza next faces 18-year-old Canadian Bianca Andreescu, who surprised China's 18th-seeded Wang Qiang 7-5, 6-2.
Andreescu, who roared to her first WTA final as a qualifier in Auckland in January - beating two former world number ones on the way - is in the quarter-finals of one of the WTA's elite premier mandatory events for the first time.
Andreescu improved her match record for 2019 to 25-3, including qualifying as she became the youngest player to make the last eight at Indian Wells since a 17-year-old Anastasia Pavlyuchenkova reached the semis in 2009.
OSAKA EYES QUARTER-FINALS
Later on Tuesday, Japan's world number one Naomi Osaka continues her title defense with an intriguing match-up against another 21-year-old - Switzerland's Belinda Bencic.
Bencic was a junior circuit star who won a WTA title in Toronto in 2015 before a series of back and wrist injuries stalled her career.
Osaka recalled playing Bencic in the Hopman Cup in 2018 "when you guys didn't know who I was".
That was months before Osaka made this prestigious premier mandatory event her first WTA title, launching her on a trajectory that would include a US Open triumph before 2018 ended.
Bencic, meanwhile is coming off her first WTA victory in four years in Dubai, where she stunned two-time Wimbledon champion Petra Kvitova in the final.
"I think that's really amazing, the things that she's done and the fact that she was able to come back from her injury and still play at a really top level," Osaka said.
"I know we both really want to win this next match."
The winner will face either fifth-seeded Czech Karolina Pliskova or Estonia's Arnett Kontaveit who met later on a day that also saw former world number ones Simona Halep, Venus Williams and Angelique Kerber vying for quarter-final berths.