In discussing Serena Williams, Chris Evert addressed some of the 19-time Grand Slam champion’s competitors, including Caroline Wozniacki. Evert, an 18-time Grand Slam champion who was just named the official ambassador of the BNP Paribas WTA Finals in Singapore, recalled Wozniacki’s 7-6 in the third loss to Williams last year at the season-ending event.

Wozniacki has reached two Grand Slam finals, both at the U.S. Open, but the former No. 1 hasn't won a Premier-level event since 2012.

“I’m a little surprised that she has threatened Serena like she has,” Evert told TENNIS.com. “With her game she is getting so much better, yes, getting more aggressive. But the fact that she doesn't have that killer serve, I just think anybody that's going to beat Serena has got to have a killer serve to win free points.

Evert has more faith in younger players Madison Keys, Sloane Stephens, and Eugenie Bouchard. They are all playing Indian Wells this week, and Evert believes they can each win Grand Slam titles in the future. Stephens will play Williams in the fourth round.

“I think Sloane, boy, I like the way she played her match. I was really happy for her,” Evert said. “I think [coach Nick Saviano] is going to be great for her. I don't know why Genie Bouchard didn't stick with [Nick].

“The way [Madison Keys] looked in Australia, I think on grass she's going to be tough. I don't think on clay as tough, but I think on grass. [But I’m impressed] with her serve, because of her return, her long reach. I think Madison definitely could be a contender for Wimbledon, absolutely.”

Bouchard, who reached two Grand Slam semifinals and the Wimbledon final last year, is only playing her third tournament this year. The Canadian fell to Maria Sharapova in the Australian Open quarterfinals and lost her opening-round match at Antwerp to Mona Barthel.

“I don't think she's going to do as well in the Grand Slams as she did last year,” Evert said. “I'm not going to say she's not going to have a good year, but I definitely think she hasn't started out great. Nothing has happened since Wimbledon last year.

“I think she doesn't look as sharp as she did in the Grand Slams, let's put it that way, right now. But knowing her and how determined she is, and she's determined, that mental toughness, that could get her right back up to where she was for sure.”