Madrid - Naomi Osaka said she switched into "zombie mode" in the final set to swat aside Spain's Sara Sorribes Tormo in Tuesday's second-round match at the Madrid Open.
Top seed Osaka was taken to three sets by world number 73 Sorribes Tormo before the Japanese star stepped up her game to close out a 7-6 (7/5), 3-6, 6-0 victory.
"In the third set, I just, like, went zombie mode," said Osaka, who has won the last two Grand Slam titles at the US Open and Australian Open.
"I just thought of everything that I had to do to win - not necessarily the outcome, but just like the little things in between every game.
"The match was basically on my racquet, she wasn't going for winners.
"The points ended by me making a winner or an unforced error. But I was a bit unfocused in the second set."
Osaka has struggled since splitting with her coach Sascha Bajin in February while an abdominal injury forced her to withdraw from the Stuttgart WTA tournament recently, creating doubts about her challenge at the French Open later this month.
She will meet Aliaksandra Sasnovich of Belarus for a place in the quarter-finals.
Results from the ATP and WTA tournaments in Madrid on Tuesday (x denotes seeding):
Jeremy Chardy (FRA) bt Albert Ramos-Vinolas (ESP) 6-2, 4-6, 7-5
Diego Schwartzman (ARG) bt Marco Cecchinato (ITA x16) 6-0, 4-6, 6-1
Marton Fucsovics (HUN) bt David Goffin (BEL) 6-4, 7-5
Fabio Fognini (ITA x10) bt Kyle Edmund (GBR) 6-4, 6-3
Adrian Mannarino (FRA) bt Joao Sousa (POR) 7-5, 5-7, 6-1
Hubert Hurkacz (POL) bt Alex De Minaur (AUS) 6-3, 6-4
Hugo Dellien (BOL) bt Gilles Simon (FRA) 4-6, 6-1, 7-6 (7/4)
Stan Wawrinka (SUI) bt Pierre-Hugues Herbert (FRA) 6-2, 6-3
Guido Pella (ARG) bt Daniil Medvedev (RUS x12) 6-2, 1-6, 6-3
Novak Djokovic (SRB x1) bt Taylor Fritz (USA) 6-4, 6-2
Naomi Osaka (JPN x1) bt Sara Sorribes Tormo (ESP) 7-6 (7/5), 3-6, 6-0
Aliaksandra Sasnovich (BLR) bt Anna Karolina Schmiedlova (SVK) 6-2, 6-2
Simona Halep (ROU x3) bt Johanna Konta (GBR) 7-5, 6-1
Petra Martic (CRO) bt Angelique Kerber (GER x4) walkover