Keys backs mature Osaka to challenge Serena in US Open final

Naomi Osaka will aim to win her first major title against 23-time grand slam champion Serena Williams, and Madison Keys rates her chances.

Madison Keys (L) and Naomi Osaka (R) after their US Open semi-final   -  Getty Images

Madison Keys was impressed by the maturity Naomi Osaka showed in their US Open semi-final and backed the Japanese to give Serena Williams a serious challenge in the final.

Osaka, 20, booked a place in her first grand slam final by defeating 2017 US Open runner-up Keys 6-2, 6-4 on Thursday, putting her one match away from just a second WTA Tour title.

The world number 19 overcame Karolina Pliskova and Simona Halep to win the Indian Wells Masters in March and Keys has no doubt she can push Williams, who is in her second grand slam final since returning from giving birth to her daughter last September.

"I think if she plays like she did [on Thursday], she can definitely give Serena a run for her money. It will be a really good match. I'm for sure going to watch it," said Keys.

"She definitely executed the best that I've ever played against her. I think there was really two games where I didn't play perfect tennis, and that was why I lost. It was really impressive. For a first-time semi-finalist on a big stage and all that, it was really impressive she held her nerve the entire time, never really had any kind of slip-up.

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"Previously I've felt like maybe I didn't play as well. I was more disappointed just in my level of tennis. But I have to say, being down a set and a break, being 100 per cent committed to fighting through the entire second set, I'm not disappointed in that. I'm walking away with a lot of good thoughts and feelings, just obviously disappointed I didn't get the outcome I wanted."

Williams advanced with a 6-3, 6-0 win over Anastasija Sevastova and is aiming to win her 24th major in her 31st grand slam final appearance Sevastova struggled to cope with the 36-year-old, who she felt improved as the match went on.

"I think she played very good. She has an amazing serve. It's tough to return. She makes so much pressure on the first, second ball, it's tough for me," she said, adding, "But I moved well. I got in the game actually pretty well. I knew what to expect. I was ready. But somehow maybe I started playing a little bit worse and worse. But she was getting better."

Asked if Williams is the best player in the world despite being ranked 26th, Sevastova said: "It's tough to say. I mean, she played finals in Wimbledon. She's playing finals here. Obviously, I think this year is not bad for her. But she has 23 grand slams. So you have your answer, I think. She's one of the best."