Former world number one Caroline Wozniacki on Friday backed her close friend Serena Williams to beat Steffi Graf's record of 22 major titles despite her heartbreaking defeat at the US Open.
Williams was bidding for the first calendar year Grand Slam since Graf in 1988, as well as a record-equalling 22nd major victory, when she was stunned by Roberta Vinci in the US Open semi-finals.
But Wozniacki, speaking during a promotional visit for the Singapore Tourism Board, said it was only a matter of time before Williams makes the Grand Slam record her own.
"She's won three Slams this year. I think that just proves it," Denmark's Wozniacki, ranked sixth, said of the American world number one.
"It's never easy (to surpass Steffi Graf) but I definitely believe that she can do it," the 25-year-old added.
With Williams, who will turn 34 next week, and Swiss great Roger Federer, also 34, still at the top of the game, Wozniacki said players are finding ways to take better care of their bodies.
"I think if you look at tennis nowadays, people play longer and I think they've found better ways to take care of their body... and everything has helped players to play longer and I think that's great," said Wozniacki.
For herself, Wozniacki stressed that staying healthy is her priority after a season affected by injury.
"I spend a lot of time in the gym to keep myself fit and healthy, it's very important now and it's probably more important than hitting balls in the court," said Wozniacki, who mixes gym work, boxing and swimming into her training regime.
The 25-year-old said she'll be looking to pick up points in Japan and China in the coming weeks to make sure she qualifies for the year-ending WTA Finals in Singapore, featuring the top eight players.
"I am going to try and do my best to qualify, I've had a few good weeks and it should be all good."