Reigning US Open champion and world's no.1 Serena Williams might have indirectly confirmed the end of her relationship with French coach Patrick Mouratoglou, clearing once and for all she's single and not dating anyone.

Williams, who recently captured her 18th Grand Slam championship with a dominant victory over Caroline Wozniacki 6-3, 6-3, stressed that she's pretty much single and asked everyone to stop speculating about her lovelife.

"To answer all your questions I'm single and I have been single so the speculations can stop," Williams posted on her Twitter account.

Williams' comment on the micro-blogging site confirmed reports last February she and Mouratoglou were no longer an item. There are some who believed the emotional distress caused by the breakup affected Williams' performance throughout the season until she turned it around just in time for the US Open championships.

"Some people will always choose a terrible choice even though they have a rainbow in front of them. But now that rainbow is gone," posted Williams, who now tied Martina Navratilova and Chris Evert with 18 Grand Slam titles around their belts.

Mouratoglou and Williams Relationship

The intimate relationship between Williams and her coach was first reported last year in the wake of her alleged breakup with Grigor Dimitrov, who is currently in relationship with Russian star Maria Sharapova.

Both parties did not confirm nor deny their status, but paparazzi spotted the two getting cuddly to each other in several occasions. Last July, the tennis star's suspected romance with Mourataglou reached its peak when German tabloid Bild reported about her pregnancy with the French coach's baby.

There are also rumors that he was influenced by drugs after experiencing a scare at the Wimbledon Open, but Williams downplayed all the speculations in an interview with USA Today.

"I have nothing to hide," the American told USA Today. "No, I didn't take anything. If you want to ask me if I took drugs, I didn't take drugs. I'm not on drugs. I've heard it all. I'm not pregnant; I wasn't pregnant. Although I think a baby would be great, but there's a time and place for everything. But no, I don't do drugs. Never did 'em. I'm scared of 'em. I'm not on that stuff."

Word had gone around that some in the women's locker room that day, watching her distress live on TV, were pantomiming Serena drinking. But, Williams says, she wasn't drunk, either. "God, no," she says, laughing. "I wish."