Defending champion Angelique Kerber was yesterday knocked out in round one of the US Open by Japanese teenager Naomi Osaka.

The German sixth seed was overpowered by the 19-year-old world number 45, who won 6-3 6-1 under the roof on Arthur Ashe Stadium at Flushing Meadows.

It continues a disappointing year for 29-year-old Kerber, who has not won a title since her victory in New York 12 months ago. She was also beaten in the first round of the French Open.

Osaka, who led Madison Keys 5-1 in the final set in round three of last year’s US Open before losing, said: “It means a lot, especially since last time I was here.

“This court has not given me fond memories but hopefully this overtakes that.
“When it was 4-1 today I was thinking, ‘I really hope I don’t do what I did last year’ and that let me focus a lot.”

Two-time Grand Slam champion Kerber struggled badly with her second serve, winning only 37% of points behind it.
Osaka hit 22 winners to Kerber’s nine, while the German also made 23 unforced errors in an erratic display.