London - Petra Kvitova, the two-time Wimbledon champion and the bookmakers' favourite for the 2017 title, was knocked out in the second round on Wednesday.
The Czech 11th seed lost 6-3, 1-6, 6-2 to Madison Brengle of the United States.
Kvitova, who is playing in her second Grand Slam since recovering from a terrifying knife attack in her home, needed to call for medical assistance during the third set.
Kvitova made 50 unforced errors during the match on Court Two.
Wimbledon results on Wednesday, the third day of the 2017 championships at the All England Club (x denotes seeding):
Men
2nd rd
Andy Murray (GBR x1) bt Dustin Brown (GER) 6-3, 6-2, 6-2
Fabio Fognini (ITA) bt Jir Vesel (CZE) 7-6 (7/3), 6-4, 6-2
Benot Paire (FRA) bt Pierre-Hugues Herbert (FRA) 7-6 (7/4), 6-1, 6-4
Jerzy Janowicz (POL) bt Lucas Pouille (FRA x14) 7-6 (7/4), 7-6 (7/5), 3-6, 6-1
Jo-Wilfried Tsonga (FRA x12) bt Simone Bolelli (ITA) 6-1, 7-5, 6-2
Sam Querrey (USA x24) bt Nikoloz Basilashvili (GEO) 6-4, 4-6, 6-3, 6-3
Kevin Anderson (RSA) bt Andreas Seppi (ITA) 6-3, 7-6 (7/4), 6-3
Ruben Bemelmans (BEL) bt Daniil Medvedev (RUS) 6-4, 6-2, 3-6, 2-6, 6-3
Karen Khachanov (RUS x30) bt Thiago Monteiro (BRA) 2-6, 7-6 (7/5), 7-6 (7/3), 7-5
Aljaz Bedene (GBR) bt Damir Dzumhur (BIH) 6-3, 3-6, 6-3, 6-3
Gilles Muller (LUX x16) bt Luks Rosol (CZE) 7-5, 6-7 (7/9), 4-6, 6-3, 9-7
Kei Nishikori (JPN x9) bt Sergiy Stakhovsky (UKR) 6-4, 6-7 (7/9), 6-1, 7-6 (8/6)
Roberto Bautista Agut (ESP x18) bt Peter Gojowczyk (GER) 6-2, 6-1, 3-6, 6-3
Steve Johnson (USA x26) bt Radu Albot (MDA) 6-3, 6-3, 4-6, 6-3
Marin Cilic (CRO x7) bt Florian Mayer (GER) 7-6 (7/2), 6-4, 7-5
1st rd
Paolo Lorenzi (ITA x32) bt Horacio Zeballos (ARG) 7-6 (7/3), 4-6, 7-6 (10/8), 7-5
Women
2nd rd
Dominika Cibulkova (SVK x8) bt Jennifer Brady (USA) 6-4, 6-4
Ana Konjuh (CRO x27) bt Irina Begu (ROM) 7-6 (7/3), 2-6, 6-3
Naomi Osaka (JPN) bt Barbora Strcov (CZE x22) 6-1, 0-6, 6-4
Venus Williams (USA x10) bt Qiang Wang (CHN) 4-6, 6-4, 6-1
Carina Witthoeft (GER) bt Aryna Sabalenka (BLR) 7-6 (7/5), 3-6, 6-3
Elina Svitolina (UKR x4) bt Francesca Schiavone (ITA) 6-3, 6-0
Johanna Konta (GBR x6) bt Donna Vekic (CRO) 7-6 (7/4), 4-6, 10-8
Maria Sakkari (GRE) bt Kristna Plskov (CZE) 6-7 (6/8), 6-4, 6-4
Madison Brengle (USA) bt Petra Kvitova (CZE x11) 6-3, 1-6, 6-2
Victoria Azarenka (BLR) bt Elena Vesnina (RUS x15) 6-3, 6-3
Heather Watson (GBR) bt Anastasija Sevastova (LAT x18) 6-0, 6-4