Paris - Former world No 1 Caroline Wozniacki collapsed to a 0-6, 6-3, 6-3 loss to Russian world No 68 Veronika Kudermetova in the French Open first round on Monday.
The Danish 13th seed had retired injured from her two previous matches in the lead-up to Roland Garros, but looked to have found form in a one-sided opening set.
Last year's Australian Open champion lost her way in the second set, though, making 10 unforced errors, before the 22-year-old Kudermetova cruised to victory in the decider on a sparsely-populated Court Philippe Chatrier.
"I was a little bit nervous at the start of the match, but I took it game by game and tried to be more aggressive," said the Russian.
Kudermetova will face either Kazakhstan's Zarina Diyas or French wildcard Audrey Albie in the second round.
Results from the second day of the French Open on Monday (x denotes seeding):
Men
First round
Novak Djokovic (SRB x1) bt Hubert Hurkacz (POL) 6-4, 6-2, 6-2
Henri Laaksonen (SUI) bt Pedro Martinez (ESP) 6-1, 6-0, 7-6 (7/4)
Salvatore Caruso (ITA) bt Jaume Munar (ESP) 7-5, 4-6, 6-3, 6-3
Gilles Simon (FRA x26) bt Sergiy Stakhovsky (UKR) 6-3, 6-3, 6-4
Jan-Lennard Struff (GER) bt Denis Shapovalov (CAN x20) 7-6 (7/1), 6-3, 6-4
Radu Albot (MDA) bt Tennys Sandgren (USA) 7-6 (7/3), 7-6 (7/1), 3-6, 6-1
Lloyd Harris (RSA) bt Lukas Rosol (CZE) 6-1, 4-6, 2-6, 6-1, 6-2
Borna Coric (CRO x13) bt Aljaz Bedene (SLO) 6-1, 6-7 (4/7), 6-4, 6-4
Dominic Thiem (AUT x4) bt Tommy Paul (USA) 6-4, 4-6, 7-6 (7/5), 6-2
Alexander Bublik (KAZ) bt Rudolf Molleker (GER) 7-5, 6-7 (4/7), 6-1, 7-6 (7/2)
Pablo Cuevas (URU) bt Maxime Janvier (FRA) 6-4, 6-4, 6-2
Roberto Carballes Baena (ESP) bt Alexandre Muller (FRA) 6-4, 6-4, 6-2
Filip Krajinovic (SRB) bt Frances Tiafoe (USA x32) 6-2, 4-6, 6-3, 3-6, 6-0
Stan Wawrinka (SUI x24) bt Jozef Kovalik (SVK) 6-1, 6-7 (3/7), 6-2, 6-3
Cristian Garin (CHI) bt Reilly Opelka (USA) 7-6 (7/0), 7-5, 7-6 (9/7)
Jo-Wilfried Tsonga (FRA) bt Peter Gojowczyk (GER) 7-6 (7/4), 6-1, 4-6, 6-3
Alex De Minaur (AUS x21) bt Bradley Klahn (USA) 6-1, 6-4, 6-4
Pablo Carreno Busta (ESP) bt Joao Sousa (POR) 6-3, 6-1, 6-2
Benoit Paire (FRA) bt Marius Copil (ROU) 6-4, 6-7 (5/7), 6-0, 6-1
Pierre-Hugues Herbert (FRA) bt Daniil Medvedev (RUS x12) 4-6, 4-6, 6-3, 6-2, 7-5
Juan Ignacio Londero (ARG) bt Nikoloz Basilashvili (GEO x15) 6-4, 6-1, 6-3
Richard Gasquet (FRA) bt Mischa Zverev (GER) 6-3, 6-4, 6-3
Corentin Moutet (FRA) bt Alexey Vatutin (RUS) 6-4, 7-6 (8/6), 6-4
Guido Pella (ARG x19) bt Guido Andreozzi (ARG) 7-6 (7/2), 6-4, 1-6, 6-1
Miomir Kecmanovic (SRB) bt Denis Kudla (USA) 6-0, 6-7 (7/9), 5-7, 6-3, 6-4
Yannick Maden (GER) bt Kimmer Coppejans (BEL) 7-6 (7/0), 7-5, 6-3
Rafael Nadal (ESP x2) bt Yannick Hanfmann (GER) 6-2, 6-1, 6-3
Women
First round
Serena Williams (USA x10) bt Vitalia Diatchenko (RUS) 2-6, 6-1, 6-0
Sofia Kenin (USA) bt Giulia Gatto-Monticone (ITA) 6-3, 5-7, 6-2
Su-Wei Hsieh (TPE x25) bt Viktorija Golubic (SUI) 6-4, 3-6, 6-0
Andrea Petkovic (GER) bt Alison Riske (USA) 2-6, 6-3, 7-5
Danielle Collins (USA) bt Tatjana Maria (GER) 6-0, 6-2
Ashleigh Barty (AUS x8) bt Jessica Pegula (USA) 6-3, 6-3
Ekaterina Alexandrova (RUS) bt Mihaela Buzarnescu (ROU x30) 6-4, 6-4
Samantha Stosur (AUS) bt Barbora Strycova (CZE) 6-2, 7-6 (7/3)
Aliona Bolsova Zadoinov (ESP) bt Vera Zvonareva (RUS) 6-4, 6-2
Sorana Cirstea (ROU) bt Kaja Juvan (SLO) 5-7, 6-4, 7-5
Jennifer Brady (USA) bt Ivana Jorovic (SRB) 7-6 (7/5), 4-6, 7-5
Polona Hercog (SLO) bt Aliaksandra Sasnovich (BLR x32) 4-6, 6-2, 8-6
Rebecca Peterson (SWE) bt Yulia Putintseva (KAZ) 6-3, 7-5
Donna Vekic (CRO x23) bt Liudmila Samsonova (RUS) 6-2, 6-4
Johanna Konta (GBR x26) bt Antonia Lottner (GER) 6-4, 6-4
Lauren Davis (USA) bt Kristyna Pliskova (CZE) 6-2, 6-4
Viktoria Kuzmova (SVK) bt Alize Cornet (FRA) 6-4, 6-3
Kiki Bertens (NED x4) bt Pauline Parmentier (FRA) 6-3, 6-4
Shelby Rogers (USA) bt Astra Sharma (AUS) 6-3, 6-3
Carla Suarez Navarro (ESP x28) bt Dayana Yastremska (UKR) 2-6, 7-6 (7/0), 6-0
Elise Mertens (BEL x20) bt Tamara Zidansek (SLO) 6-4, 3-6, 6-2
Diane Parry (FRA) bt Vera Lapko (BLR) 6-2, 6-4
Mandy Minella (LUX) bt Anastasia Pavlyuchenkova (RUS) 6-4, 6-2
Anastasija Sevastova (LAT x12) bt Luksika Kumkhum (THA) 6-1, 6-4
Veronika Kudermetova (RUS) bt Caroline Wozniacki (DEN x13) 0-6, 6-3, 6-3
Zarina Diyas (KAZ) bt Audrey Albie (FRA) 6-2, 6-2
Zhang Shuai (CHN) bt Varvara Lepchenko (USA) 6-1, 6-1
Kaia Kanepi (EST) bt Julia Goerges (GER x18) 7-5, 6-1