Billie Jean King says the emergence of the next generation of WTA stars makes it impossible to call who will win the US Open at Flushing Meadows.
With the pregnant Serena Williams absent the women's draw is wide open in New York, with Simona Halep, Karolina Pliskova, Garbine Muguruza and Angelique Kerber all fancied for the title.
Since Williams won in Melbourne there have been two different grand slam winners in 2017 - Jelena Ostapenko causing a huge shock at the French Open before Muguruza claimed her second Wimbledon crown.
As well as vying for the title over the next fortnight, the world number one spot is also in reach for eight players - strength in depth that King is delighted to see after Williams' recent dominance.
"The women's [draw is] impossible [to call]," 12-time grand slam champion King told Omnisport, courtesy of WTA-WSJ.
"You have all the young ones coming up; Muguruza who just won Wimbledon, you've got Ostapenko who just won the French.
"Halep is still young and Pliskova has come through with her big serve and she is just much more fit - in fact, she took off almost six months to get fit and now it's really showing.
"She has never won but there are eight players where at the end of the US Open they could be number one in the world.
"I think this is the most depth we have ever had, we are also seeing a changing of the guard because I have been through five six, seven generations and right now it's so exciting.
"I really love it because I don't know who is going to win and I really love that feeling because it captures my interest as a former professional player.
"It's like, who is going to break through this group and really end up being that special person like the Serena Williams, or the Martina Navratilova, the Chris Evert or the Steffi Graf and the Monica Seles or Martina Hingis.
"These special players through the years, who is going to be that breakthrough that lasts and has longevity and not just for a year or two be world number but really hang in there for a long time."
But despite the plethora of exciting talent, King is not ruling out Venus Williams for a shot at a third US Open, especially after making the Wimbledon final in July.
She added: "I would love her to do well and winning would be amazing for her, because I personally did not think she would come back to play tennis at all after Sjogren's [syndronme] and if she did come back from her Sjogren's I thought she would only play doubles.
"So I admire [her] and Venus continues to inspire me because she has been able to play singles and really hang in there and do well and getting to the finals of Wimbledon is amazing and I would like to see her do well.
"Venus is back in the hunt."