US Open champion Naomi Osaka said she had “the worst attitude” in her loss to Lesia Tsurenko in the Brisbane International semi-finals.
The Japanese second seed was visibly frustrated as she was beaten 6-2 6-4 by Ukraine’s Tsurenko in just 66 minutes.
Osaka, who won her maiden Grand Slam title in September, said the defeat had taught her “a valuable lesson”.
“I was sulking a little bit, and there are moments that I tried not to do that,” the 21-year-old explained.
“I feel like I didn’t really know how to cope with not playing well.”
The world number five made 26 unforced errors against Tsurenko, and did not create a break opportunity until late in the second set.
Osaka told her coach Sascha Bajin during the match that she did not know why she was “flat”, adding: “I’m putting myself in the situation that either I win the match or I die.”
“This helpless feeling I have, I learned sort of what I can do to improve the situation so there aren’t many moments that I feel like that.”
Osaka, who later withdrew from next week’s Sydney International, will move to fourth in the world rankings on Monday.
Canadian teenager Bianca Andreescu continued her remarkable run as she beat Hsieh Su-wei to reach the Auckland International final.
The 18-year-old previously beat Caroline Wozniacki and Venus Williams to set up the meeting with the Taiwanese third seed.
Andreescu saved four break points and hit four aces en route to a 6-3 6-3 victory.
She will face defending champion Julia Gorges on Sunday, after the German beat Slovakia’s Viktoria Kuzmova 6-1 7-6 (8-6).
In Shenzhen, Aryna Sabalenka secured the first WTA title of the year with victory over American Alison Riske.
The Belarusian won 4-6 7-6 (7-2) 6-3 to secure her third career title.