It was billed the heavyweight contest of the US Open first round but the latest duel between Serena Williams and Maria Sharapova was just as lopsided as most of their past affairs.

Naomi Osaka, 20, triumphed 6-2, 6-4 in the match marred by Serena Williams's second set outburst.

Maria Sharapova rolled into the last 16 at the US Open by overpowering US teen Sofia Kenin on Friday while a wide-open side of the men's draw lost 2014 champion Marin Cilic.

The Tennis Integrity Unit (TIU) revealed on Thursday they are investigating whether a match at this year's Wimbledon was fixed.

Third seed Stan Wawrinka rose to the occasion once again to beat top-seeded defending champion Novak Djokovic 6-7(1) 6-4 7-5 6-3 and win the US Open on Sunday for the third grand slam title of his career.

Angelique Kerber climaxed a dream season at the US Open on Saturday, performing as the champion she has become through hard work, patience and a love of the game.