Serena Williams says she wants to "move on to bigger and better things" following her first match back since her controversial US Open final defeat by Naomi Osaka.
Williams, 37, was beaten by her sister Venus 4-6 6-3 10-8 in an exhibition match in Abu Dhabi on Thursday, the BBC reports.
The 23-time Grand Slam champion subsequently refused to discuss her confrontation with umpire Carlos Ramos in September's final in New York.
"I don't avoid anything," she said.
"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 got a code violation for coaching, a penalty point for racquet abuse, and a game penalty for calling the umpire a "thief" in during the loss to Osaka.
She later accused him of sexism and was fined $17,000 for the code violations.
Speaking at the Mubadala World Tennis Championship, Williams said equalling Margaret Court's record of 24 Grand Slam titles was a "significant" goal for 2019.
Williams' first chance to tie the record will be at the Australian Open from 14-27 January.
"It has always been significant since I got 22, then 23," she said.
"It's something that I clearly want but I have to be able to get there and beat a lot of good players to get it."
She added that she felt "pretty fit" in her defeat by Venus.
"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," she added.
Before the match, Williams praised the introduction of more ranking protection for new mothers on the WTA Tour.
