World number one Naomi Osaka admits she has a long way to go to turn her mastery of hard courts onto success on grass as she prepares for Wimbledon at the Birmingham Classic this week.

Osaka has claimed her first two Grand Slams at the US and Australian Open since her last outing on a grass court, when she was thrashed for the loss of just six games by Wimbledon champion Angelique Kerber.

“Grass, I’m not really that comfortable with it,” said Osaka on Monday. “As a little kid, I never played on grass.

“It’s always the first tournament that’s the hardest. I have only practiced twice on grass because it was raining a lot. So, I guess I’m feeling as good as I can.

“It’s just really different from everything I have played on.”

Osaka, though, is keen to show how much she has improved as a player even on an unfamiliar surface over the past year.

“Whenever I come to grass I can only remember the last match I played which is always Wimbledon and last year I played against Kerber and she kind of crushed me,” she added.

“I’m going to try and think about that match of course, but think about everything that I did, like sort of improved during the year.”

And Osaka is hoping a much-needed week’s holiday after a third-round exit at the French Open will leave her rejuvenated to try and get into the second week at Wimbledon for the first time.

“It was kind of refreshing because I felt like since the US Open things have been going so fast, so I felt like I really needed a break and it was good for me.”