WTA Finals: Frustrated Naomi Osaka looking for answers after opening defeat against Sloane Stephens

Naomi Osaka was left frustrated with her performance after she opened her debut WTA Finals tournament with a 7-5 4-6 6-1 defeat against Sloane Stephens, the U.S. Open champion admitting that she never really felt comfortable against the American.

"Yeah, it was kind of hard for me. My timing was really off. I think I was, like, super far behind the baseline, which is not my playing style," the 21-year-old Japanese player told reporters after her Red Group opener on Monday, adding that she needs to practice well tomorrow to find her touch.

Osaka rarely gets animated on the court, yet the world number four spent much of the match chastising herself over unforced errors and even sank to her knees when she was broken for the second time in the deciding set.

"That was something I`m not really proud of. I feel like I play better when no one knows what I`m thinking," she said. 

Osaka added that she tended to enjoy matches more when she was nervous and that her desire to win against Stephens was one of the reasons why she became too emotional during the contest.

"I don`t think I was nervous. Being nervous is better than feeling what I felt today, which is sort of like I want to win really bad," she said. "I think when I have that type of feeling, I outwardly express more than keeping everything inside."

One crumb of comfort for Osaka is that she can still advance to the semi-finals if she wins at least one of her remaining pool matches against Angelique Kerber and Kiki Bertens.

"Yeah, I think it`s really cool that you can keep going even after you lose. I think that this tournament is really special in that way, because there is no other tournament during the year that does a round-robin format," she said.

"So I think that the fact that you get another chance to learn from your mistakes and apply it in the matches going on is something that`s really good."