Indian Wells - Sloane Stephens' struggles continued Friday as the fourth-ranked American fell 6-3, 6-0 to Swiss qualifier Stefanie Voegele in her opening match at Indian Wells.
Voegele, currently ranked 109th in the world after reaching a career high of 42, won the last eight games of the match to sweep into the third round in just 68 minutes.
It's the second tournament in a row that 2017 US Open winner Stephens has been toppled by a qualifier, coming on the heels of a straight-sets defeat to 172nd-ranked Brazilian Beatriz Haddad Maia in Acapulco.
Voegele's victory is perhaps less of a shocker. She has now won the last four of five career meetings with Stephens.
Voegele, 28, broke Stephens five times in the match, including three breaks in the second set and saved all three break points she faced.
Stephens said the windy weather was a factor, but conceded it affected her opponent just as much.
"I didn't play well," Stephens said. "It was unfortunate that I lost the second set 6-0. It happens."
Two-time Grand Slam champion Garbine Muguruza breezed into the third round on a blustery day in the California desert, defeating American Lauren Davis 6-1, 6-3.
"I think we played good, considering the wind," Muguruza said. "I was happy with finding my game, even if it's not a day that you can hit the ball and feel great."
Muguruza, seeded 20th, next faces another former world number one -- either 23-time Grand Slam champion Serena Williams or Victoria Azarenka, who highlighted the night session on the main stadium court.
Williams, seeded 10th, has won 17 of 21 meetings with Azarenka, but the Belarusian won their most recent clash, in the Indian Wells final in 2016.
Azarenka, trying to claw her way back among the game's elite from her current 48th in the world, is coming off a first-round win over compatriot Vera Lapko.
Whatever the outcome, Muguruza was looking forward to the challenge and not at all dismayed by the fact that it will come so early in the tournament.
"I think it's great," the Spaniard said. "That's the matches that I feel are exciting, that I want to play."
World number two Simona Halep was also in action on Friday, taking on Czech Barbora Strycova for a place in the third round.
World number one and defending champion Naomi Osaka was due to open her campaign on Saturday against Kristina Mladenovic.
France's Mladenovic upset Osaka in Dubai last month in the Japanese star's first match since she lifted her second Grand Slam title at the Australian Open in January.
Results on Friday in the BNP Paribas Open WTA and ATP Masters hardcourt tournament (x-denotes seeded player):
Hubert Hurkacz (POL) bt Donald Young (USA) 6-3, 6-3
Steve Johnson (USA) bt Taylor Fritz (USA) 6-3, 6-3
Dusan Lajovic (SRB) bt Taro Daniel (JPN) 7-6 (8/6), 6-4
Radu Albot (MDA) bt Marius Copil (ROM) 6-2, 6-2
Stan Wawrinka (SUI) bt Daniel Evans (GBR) 6-7 (4/7), 6-3, 6-3
Peter Gojowczyk (GER) bt Andreas Seppi (ITA) 7-5, 6-4
Alexei Popyrin (AUS) bt Jaume Munar (ESP) 7-6 (9/7), 6-3
Alex Bolt (AUS) bt Ernests Gulbis (LAT) 6-3, 5-7, 6-2
Robin Haase (NED) bt Denis Istomin (UZB) 7-6 (7/2), 6-1
Feliciano Lopez (ESP) bt Tomas Berdych (CZE) 7-6 (7/3), 7-6 (7/2)
Filip Krajinovic (SRB) bt Mikhail Kukushkin (KAZ) 6-3, 6-4
Johanna Konta (GBR) bt Hsieh Su-Wei (TPE x27) 6-0, 6-2
Garbine Muguruza (ESP x20) bt Lauren Davis (USA) 6-1, 6-3
Stefanie Voegele (SUI) bt Sloane Stephens (USA x4) 6-3, 6-0
Wang Qiang (CHN x18) bt Bernarda Pera (USA) 7-6 (7/5), 6-2
Daria Gavrilova (AUS) bt Mihaela Buzarnescu (ROM x29) 6-2, 6-2
Jennifer Brady (USA) bt Caroline Garcia (FRA x19) 6-3, 3-6, 6-0
Marketa Vondrousova (CZE) bt Daria Kasatkina (RUS x14) 6-2, 6-1
Jelena Ostapenko (LAT x22) bt Zhang Shuai (CHN) 6-2, 6-1
Kateryna Kozlova (UKR) bt Aliaksandra Sasnovich (BLR x31) 6-4, 2-6, 6-0
Simona Halep (ROU x2) bt Barbora Strycova (CZE) 6-2, 6-4