For more than a decade, the dominant Serena Williams has loomed large over women's tennis but 18-time Grand Slam singles winner Chris Evert believes the winds of change are swirling.
Williams, with 22 slams and No. 1 for the last 178 weeks, is a seemingly immovable object at the summit but the likes of No. 2 Angelique Kerber and No. 3 Garbine Muguruza have what it takes to end her reign.
Speaking to the media in a conference call yesterday, Evert said: "Even though Serena is still the player to beat and the No. 1 player in the world, I think that there has been a shift in the other players.
"They're sort of rising to her level a little bit and starting to recognise how to play her, and they're incorporating a little more power and strategy into their game."
Williams reached the finals at the last three majors, but only emerged triumphant at Wimbledon.
Singling out Australian Open champion Kerber, Roland Garros winner Muguruza and rising star Madison Keys, Evert said: "I like how the other players are starting to challenge her a little bit and play closer matches, instead of being intimidated as they have been before.
RISE OF THE CHALLENGERS
They're starting to recognise how to play her, and they're incorporating a little more power and strategy into their game.
CHRIS EVERT, on the next wave of true contenders.
"It's the time in women's tennis to really appreciate and respect not just Serena, but also (older sister) Venus) for their contributions to the game, as well as the newcomers who are really starting to make a name for themselves."
At age 34, Williams is the oldest of the three Grand Slam champions this year - Kerber is 28 and Muguruza, 22.
But Evert, 61, cautioned against writing Williams off too quickly.
"Nobody can count Serena out as long as she is healthy and motivated," she said of her fellow American. "I think she can still win Grand Slams for the next couple of years."
Evert added that Williams has one key weapon that puts her a cut above her challengers - her serve.
Said Evert: "If you look at her statistics, she hits 10 to 15 aces every match and her serve is the greatest that we've ever seen in women's tennis.
"It does win her some easy points - once the players get into a rally with Serena they've got a pretty good shot at winning, but they've got to break that serve."
At last week's Wimbledon final, Williams served 13 aces to Kerber's none.
Evert will return to this year's WTA Finals Singapore as an ambassador, together with fellow returning ambassadors Arantxa Sanchez-Vicario and Martina Navratilova.
Evert named another player apart from Kerber, Muguruza and Keys who could challenge Williams at the season-ending tournament this year - two-time Australian Open champion Victoria Azarenka, who beat Williams in straight sets at the Indian Wells tournament in March.
Said Evert: "I always thought Azarenka would really challenge Serena and she does, she beat her this year, but she keeps getting injured.
"I don't know what her situation is health-wise, but if healthy, Azarenka is very dangerous."
The third edition of the WTA Finals Singapore will take place from Oct 23-30.