INDIAN WELLS, CA, USA - Swiss qualifier Stefanie Voegele continued her mastery of Sloane Stephens at the BNP Paribas Open on Friday.
Currently ranked World No.109 with a career-high mark of World No.42, Voegele continued her head-to-head dominance over the former US Open champion with a 68-minute, second round shocker on Friday afternoon, winning the last eight games of the match in a 6-3, 6-0 upset.
Voegele now owns a 5-1 edge over Stephens in their career meetings dating back to 2008 and has won the last four, but her Indian Wells victory marked her first two-set win in the matchup since the pair's first-ever meeting in Flushing Meadows 11 years ago.
"I played her a few times before, and she's a really good player, so I didn't expect this at all," Voegele told wtatennis.com after the match.
"She probably just doesn't like [my game] and she's getting so many balls back. Today, it was really windy, and it was not easy to put the ball in. I tried to move well and not play too close to the lines.
"I'm happy that I tried to stay in there, even when there were some points that didn't work out the way I wanted, and I'm happy about the end."
The 28-year-old broke the World No.4 five times in the match, including three times to win her first-ever bagel set against the United States' No.1, and saved all three break points she faced as the American fired 32 unforced errors over 15 games.
"Obviously, playing someone who you haven't done that well against in the past is a little bit tough. The conditions, it was windy, but windy for both of us. I just didn't play a great match today," Stephens said.
"I'm not sure [why she struggles against Voegele]. I'm still trying to figure it out, obviously. If I knew, I would probably do a little bit better."
The win is Voegele's first over a Top 10 opponent in six years, and the second of her career.
Her last win against a Top 10 opponent came at the Volvo Car Open in Charleston in 2013, when she upset No.2 seed and then-World No.10 Caroline Wozniacki in the second round to reach her first-ever Premier-level semifinal.
The qualifier will next face either the in-form Bianca Andreescu, or No.32 seed Dominika Cibulkova for a spot in the round of 16.
"Andreescu has had a very good last two, three months. She's moving really well, and playing really good," the Swiss said.
"Cibulkova, she also moves well. I will see, and it's most important to get some rest to be ready for Sunday."