Serena and Venus Williams step out in Abu Dhabi

In their first appearance on court since September’s US Open, Venus Williams beat sister Serena in a match tiebreak at the Mubadala World Tennis Championship in Abu Dhabi.

Venus, whose last competitive appearance came in a third-round loss to Serena in New York, beat her younger sibling 4-6 6-3 [10-8] in an entertaining contest on Thursday.

Serena, despite the loss, looked fit and sharp throughout the hit-out.

But she would not be drawn into discussing her last on-court appearance, which came in an explosive, controversial loss to Naomi Osaka in the US Open final.

A clarification from IMG that the request not to ask Serena about the US Open final did not come from Serena.

— Reem Abulleil (@ReemAbulleil) December 27, 2018

“I don’t avoid anything. I just don’t have time to talk about that. I talked about it, everyone talked about it for months and months and months and it’s best to move on to bigger and better things,” Williams told Sport360.

“My fitness, I feel like I’m pretty fit. I was running and running and never got tired except for one point but then I got over it in 20 seconds, so I think that was really the highlight for me.”

Abu Dhabi was where Serena first dipped her toe back into competition – in an exhibition match against Jelena Ostapenko – in late 2017, less than four months after giving birth to daughter Alexis Olympia.

She made her official comeback at Indian Wells three months later, and despite playing just seven events in 2018, she rose to world No.16 after reaching the Wimbledon and US Open finals.

Venus, however, went in reverse in 2018.

After returning to the top five in 2017 thanks to finals appearances at the Australian Open, Wimbledon and the WTA Finals, the elder Williams plummeted to No.38 and did not progress beyond the third round at any Grand Slam event.

In early December, the 38-year-old parted ways with David Witt, her coach of 11 years.

“I love everyone that I work with, and I still love them, so it’s just all love. I haven’t brought on anyone (new) yet, so we’ll see what happens,” Venus told Sport360.

She will play her first official event of 2019 at the ASB Classic in Auckland, while Serena heads to Perth to represent the United States at the Hopman Cup.