NAOMI Osaka (right) and Coco Gauff are headed to the much-anticipated third-round showdown of the US Open. AFP

NEW YORK (AFP) — Serena Williams is usually playing in the matches that thrill her most, but she’s going to join a host of fans in watching Saturday’s US Open third round showdown between teen sensation Coco Gauff and top-ranked defending champion Naomi Osaka.

I definitely think it’s the future of women’s tennis

The blockbuster night matchup at Arthur Ashe Stadium pits 15-year-old American Gauff, who made a fourth-round Wimbledon run in her Grand Slam debut, against 21-year-old Japanese star Osaka, the reigning US and Australian Open champion.

“I definitely think it’s the future of women’s tennis,” Williams said. “And I’m really excited to just be a fan girl and kind of watch.”

Williams, the 37-year-old American chasing a 24th Grand Slam title to match Margaret Court’s all-time record, sees them as the hottest young talents in the game.

“It will be a really interesting match. I think it’s super exciting tennis,” she said. “Coco is much younger than Naomi, if you could say that, because Naomi is incredibly young.”

Even world number one and defending men’s champion Novak Djokovic can’t wait to see what Gauff and Osaka do.

“Coco is definitely a new superstar of tennis. It’s great to see her fighting spirit, her intensity,” Djokovic said. “She’s only 15. She brings so much maturity in her game for such a young age. It’s very impressive.

“Definitely a fan of her and fan of Naomi, as well, what she has done in the last couple of years. It’s going to be really interesting because they’re both very likable players and girls. They have a lot of fans. It’s going to be definitely a great match.”

Gauff, the youngest player in the US Open third round since Russia’s Anna Kournikova in 1996, prepared to face Osaka by joining partner Caty McNally for a first-round doubles victory Friday.

Gauff teamed up with 17-year-old compatriot McNally to beat Germany’s Julia Goerges and Czech Katerina Siniakova 7-6 (8/6), 6-2 and said the doubles helped prepare her for Osaka.