Sloane Stephens, the 2017 US Open champion, was stunned in the first round as reigning champion Naomi Osaka confronted severe nerves to come through in three tough sets against Russia’s Anna Blinkova, the world number 84 in the first round on Tuesday.

Stephens slumped to a 6-3, 6-4 loss to Anna Kalinskaya in the first round at Flushing Meadows while Osaka, who suffered a first-round exit last month at Wimbledon, struggled to put away Blinkova before prevailing 6-4, 6-7 (5/7), 6-2.

“I have a lot of really good memories here because I grew up in this area. I don’t think I’ve ever been this nervous in my life,” said Osaka, sporting a black brace on the left knee that prompted her to retire in Cincinnati.

“You want to do well after you did well last year. I definitely didn’t want to lose in the third set.”

The top seed goes on to face Poland’s Magda Linette.

Osaka must retain her US Open crown to have a chance of remaining world number one and was tested extensively by 2015 Wimbledon junior finalist Blinkova, who raced 4-1 ahead in the first set and saved a match point in the second to force a decider.

Wimbledon champion Simona Halep, ousted in the opening round the past two years at Flushing Meadows, outlasted US lucky loser Nicole Gibbs 6-3, 3-6, 6-2.

“I feel much better that I could win a match finally in this tournament,” Halep said. “I’m not feeling great at the beginning of the tournament. But always when I played tough matches at the beginning, then I went through the semi-finals or quarter-finals. So I’m confident. I feel like my game, it’s there.”

Fifteen-year-old Wimbledon sensation Coco Gauff edged past Anastasia Potapova, 18, in three sets on her US Open debut.

Results

1st rd

Naomi Osaka (JPN x1) bt Anna Blinkova (RUS) 6-4, 6-7 (5/7), 6-2

Magda Linette (POL) bt Astra Sharma (AUS) 6-3, 6-4

Cori Gauff (USA) bt Anastasia Potapova (RUS) 3-6, 6-2, 6-4

Timea Babos (HUN) bt Carla Suarez Navarro (ESP x28) 6-2, 0-0, retired

Anett Kontaveit (EST x21) bt Sara Sorribes (ESP) 6-1, 6-1

Ajla Tomljanovic (AUS) bt Marie Bouzková (CZE) 1-6, 7-5, 6-1

Alize Cornet (FRA) bt Jessica Pegula (USA) 6-2, 6-3

Belinda Bencic (SUI x13) bt Mandy Minella (LUX) 6-3, 6-2

Kaia Kanepi (EST) bt Tatjana Maria (GER) 5-7, 7-6 (7/4), 6-3

Julia Görges (GER x26) bt Natalia Vikhlyantseva (RUS) 1-6, 6-1, 7-6 (7/1)

Francesca Di Lorenzo (USA) bt Veronika Kudermetova (RUS) 7-6 (7/4), 6-2

Anastasia Pavlyuchenkova (RUS) bt Pauline Parmentier (FRA) 6-1, 7-6 (7/2)

Kiki Bertens (NED x7) bt Paula Badosa (ESP) 6-4, 6-2

Simona Halep (ROU x4) bt Nicole Gibbs (USA) 6-3, 3-6, 6-2

Taylor Townsend (USA) bt Kateryna Kozlova (UKR) 3-6, 6-3, 6-2

Sorana Cirstea (ROU) bt Katerina Siniakova (CZE) 7-5, 6-2

Aliona Bolsova (ESP) bt Barbora Strycova (CZE x31) 6-3, 0-6, 6-1

Caroline Wozniacki (DEN x19) bt Wang Yafan (CHN) 1-6, 7-5, 6-3

Danielle Collins (USA) bt Polona Hercog (SLO) 6-3, 4-6, 6-4

Kirsten Flipkens (BEL) bt Wang Xiyu (CHN) 3-6, 6-2, 6-2

Bianca Andreescu (CAN x15) bt Katie Volynets (USA) 6-2, 6-4

Kristie Ahn (USA) bt Svetlana Kuznetsova (RUS) 7-5, 6-2

Jelena Ostapenko (LAT) bt Aleksandra Krunic (SRB) 6-3, 7-6 (9/7)

Alison Riske (USA) bt Garbine Muguruza (ESP x24) 2-6, 6-1, 6-3

Elise Mertens (BEL x25) bt Jil Teichmann (SUI) 6-2, 6-2

Kristyna Pliskova (CZE) bt Diane Parry (FRA) 6-4, 6-3

Andrea Petkovic (GER) bt Mihaela Buzarnescu (ROU) 6-3, 6-4

Petra Kvitova (CZE x6) bt Denisa Allertova (CZE) 6-2, 6-4

Donna Vekic (CRO x23) bt Richel Hogenkamp (NED) 7-6 (7/4), 6-3

Yulia Putintseva (KAZ) bt Madison Brengle (USA) 6-3, 6-3

Aryna Sabalenka (BLR x9) bt Victoria Azarenka (BLR) 3-6, 6-3, 6-4