What will be remembered from a 2-6, 6-3, 5-10 defeat to Jelena Ostapenko in Abu Dhabi is that after a year away from professional competition, after giving birth in September, getting married in November and adjusting to huge changes in her life, Williams stepped back on the court and proved - once again - that she won't be stopped.
The 36-year-old American, victor of 23 grand slam single titles, was making a comeback after taking almost 11 months off to have her first child.
That's not bad for someone who hasn't played competitive tennis in almost a year, all things considered.The legendary athlete last took the tennis court in January, when she defeated her sister Venus in the climactic finale of the Australian Open.
The American made it clear that she was not going to retire and felt there were still a few years left in the legs, but it seemed as though she might struggle to make it back in time for the Australia Open in January.
Serena Williams was "excited to be back" after completing her first match since giving birth fourth months ago.
"I am taking it one day at a time. I am going to assess everything with Patrick [Mouratoglou, her coach] and my team".More news: Reliance giving new year's wishes by introducing the Happy New Year Offer
In the second set she was, however, far more recognisable as the 23-times Grand Slam victor who has reigned the women's game for so long.
However, she found more timing as the match progressed, increasing the speed on her serve and moving well inside the court.
After the initial break, Ostapenko latched onto the weak serves of Williams, and several unforced errors helped, as she stormed back into the match to go 4-1 up with two breaks. Another break in the ninth game delivered her first set of the comeback.
In an on-court interview, Williams talked about her experience as a mother. "I don't think I am going to rate my performance", Williams said.
"But it's really good. But as the match moved on, I was less afraid", explained Williams.
Meanwhile, Ostapenko sounded delighted in her official statement, mentioning, "I am thrilled to be playing in Abu Dhabi at the Mubadala World Tennis Championship".