Caroline Wozniacki denies tweet was a dig at Rory McIlroy

Tennis star Caroline Wozniacki has denied that her tweet backing golfer Jason Day to win the US Open was a dig at her former fiance Rory McIlroy.

After Day collapsed on the ninth green on Friday due to vertigo, Wozniacki publicly backed the Australian to go all the way and claim the Major title.

The 27-year-old failed to do so as he finished tied ninth with McIlroy, but ahead of the final round, questions were raised when Wozniacki tweeted: "After everything @JDayGolf has been thru this week and the fight and grit he has shown, I'm rooting for him to win it all today!"

When asked in a press conference at Eastbourne on Monday if the tweet was a dig at Wozniacki's former fiance, the tennis star said: "I comment on sports all the time. Nothing I do has anything to do with my ex.

"What Jason Day has been through this week with collapsing on the course and everything and still keeping going and having the doctor out there for the full round [on Sunday], I think anyone who follows sports in general knows that's a great effort to keep going, not give up and still do so well."

Wozniacki and McIlroy split up in May last year after the golfer called off the couple's engagement.