Nishikori backs Osaka to give Serena strong US Open challenge

Naomi Osaka is the first Japanese woman to reach a Grand Slam final, where she'll be taking on 23-time major winner Williams.

Naomi Osaka celebrates her victory over Madison Keys after their 2018 US Open women's singles semi-finals.

Kei Nishikori couldn't make it two Japanese players in the US Open finals, but he backed compatriot Naomi Osaka to give Serena Williams a run for her money in the women's championship match.

“I'm sure she's going to have a chance to beat Serena,” Nishikori said Friday. “I think Naomi can stay with her.”

Osaka, 20, is the first Japanese woman to reach a Grand Slam final, where she'll be taking on 23-time major winner Williams.

Osaka and Nishikori had already made history as the first Japanese duo to reach the women's and men's semi-finals at the same Slam.

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However Nishikori, runner-up to Marin Cilic in the 2014 US Open, couldn't take the next step, falling to Wimbledon champion Novak Djokovic 6-3, 6-4, 6-2 on Friday.

Nishikori, the first man representing an Asian country to make a Grand Slam final, was asked if he had any advice for Osaka.

“I think she's going to be fine,” he said after watching Osaka beat 2017 runner-up Madison Keys in straight sets to reach the final.

“She was playing unbelievable tennis,” he said. “I'm sure it's different, finals and semis, but I hope she can enjoy it and play a good level.”