Williams who gave birth to her first child earlier this year will play current French Open victor Jelena Ostapenko on day three (December 30) at 5pm as she prepares for the year's first Grand Slam next month.
However, despite impressing after taking a set off the No. 7-ranked Ostapenko after almost a year away from tennis, Williams conceded she is still undecided whether she will defend her Australian Open title when the first major of the year gets underway in Melbourne on January 15.
Williams also has more grand slam singles titles - 23 - than the age of her rival Saturday, Ostapenko.
She was able to mop up the drives of the explosive Ostapenko and produce a surfeit of winners herself while her serve slowly cranked into action.
"The first match is always really hard after a break", Williams said.
It was not unlike Andy Murray the previous day in that it took her four or five games to properly find her stride.More news: The Last Jedi scene causing movie theaters to post warning
"I am hoping next year I can get back to that and if I do then I have an opportunity to compete for the biggest tournaments in the world and I still believe that".
"I think I lost all three-set matches (after that) besides the match in London, so that was not very good for my confidence - I need confidence to play good tennis". It's my first time playing in Abu Dhabi. I felt great on the court, the surface feels great for my game.
"She was actually my idol when I was growing up, and I saw her matches and I really liked the style she was playing. But at one point you have to also make a breakthrough at the majors and I think 2018 is the time for it", said Thiem.
"Given the changes and everything she would've gone through I wouldn't expect her to be out here if she doesn't feel like she's ready to play at her best".
Her unwillingness to make public any planned appearances other than Abu Dhabi leaves observers to wonder if she wants to wait and see how her training goes.
The 33-year-old former US Open champion says she expects to play next summer's circuit at least and will be looking to improve on a first-round exit at Pat Rafter Arena last summer to seeded Garbine Muguruza.