Japan's Kei Nishikori and Naomi Osaka were both knocked out in straight sets in the first round of the Rogers Cup on Tuesday.

In the men's singles at Toronto's Aviva Centre, Nishikori was defeated 7-5, 6-1 by world No. 39 Robin Haase. The Dutchman's serve proved the difference as he put 11 aces past the former world No. 4.

Nishikori, currently ranked 22nd, took three straight games in the first set to book an early lead but imploded in the fifth game with three double faults.

"I made a lot of mistakes," Nishikori said. "I broke him early in the first set and might have advanced had I extended the lead more, but I gradually allowed my opponent's game to take over."

Nishikori reached the Rogers Cup final in 2016 but lost to his bogeyman, Serbia's Novak Djokovic.

In the women's singles at IGA Stadium in Montreal, Osaka was narrowly beaten in a hard-fought first set tiebreaker and could not maintain her level of play in the second, falling to a 7-6(2), 6-2 loss to Spain's Carla Suarez Navarro in a rain-affected match.

In the women's doubles, Japanese pair Miyu Kato and Makoto Ninomiya advanced to the second round after beating Ukrainian Nadiia Kichenok and Russian-born Australian Anastasia Rodionova 7-5, 4-6, 10-7.

(Naomi Osaka)
[Getty/Kyodo]