Mihaela Buzarnescu has her eyes on more than one prize on Sunday, knowing that victory over Maria Sakkari in the Silicon Valley Classic final will lift her into the world's top 20.

The fifth seed booked her place in the San Jose showpiece with an impressive comeback win over Elise Mertens, winning four games in a row in the second set to turn the tide after losing the opener.

Mertens required medical attention for a right forearm injury and Buzarnescu powered on to claim the last six games and a 4-6 6-3 6-1 victory.

The Romanian climbs to a provisional 21st in the WTA rankings with Saturday's result, but knows she is merely one win away from a place in the top 20, a dream since her childhood.

"I think what I'm most proud of from my week so far is that my ranking will be higher next week," Buzarnescu said. "That's a big achievement that I'm really proud of.

"If I will get top 20 - like my goal since I was 14 - that's going to be an amazing feeling."

Sakkari stands in her way, playing her first WTA Tour final after similarly fighting back to defeat Danielle Collins 3-6 7-5 6-2.

"I think it's part of my character and the way I grew up playing," said Sakkari, who knocked out Venus Williams in the last eight. "I like drama!"

Elsewhere, 2014 champion Svetlana Kuznetsova will face Donna Vekic in the Citi Open final.

Kuznetsova beat Andrea Petkovic 6-2 6-2, before seventh seed Vekic saw off Zheng Saisai 7-5 6-3 in Washington DC on Saturday.

Ahead of learning the identity of her opponent, former world number two Kuznetsova said: "I'll see whoever wins that match and just prepare my tactics.

"They're two very different players, and both of them are going to be really difficult opponents for the final, but I'm just looking forward to playing."