ABU DHABI, United Arab Emirates -- Serena Williams lost on her return to competitive tennis after giving birth, going down to French Open champion Jelena Ostapenko in an exhibition in the United Arab Emirates on Saturday.
"I don't think I am going to rate my performance," Williams said. "I have plenty of comebacks, from injuries, from surgeries, but I've never had a comeback after actually giving birth to a human being. So, in my eyes, I feel it was a wonderful, wonderful match for me."
Williams struggled with her serve and Ostapenko won 6-2, 3-6 and then 10-5 in a super tiebreaker, but the American still impressed to take a set off the No. 7-ranked Ostapenko after nearly a year away from tennis.
Williams said after the 67-minute match at the Mubadala World Tennis Championship that she is still undecided on her title defense of the Australian Open, which starts Jan. 15, but delivered a warning to rivals.
"I don't know if I am totally ready to come back on the tour yet. I know that when I come back I definitely want to be competing for championships," Williams said. "I am definitely looking forward to getting back out there.
"I am taking it one day at a time. I am going to assess everything with my team before deciding."
The 36-year-old Williams took time off after winning the Australian Open last January while pregnant. She gave birth to her first child, a girl named Alexis Olympia Ohanian Jr., on Sept. 1. She married Reddit co-founder Alexis Ohanian in November.
Williams has won 23 Grand Slam singles titles, a record for the professional era.
"Knowing that I have won 23 Grand Slam titles and several other titles, I don't think I have anything more left to prove. But I am not done yet," Williams said.
Despite winning her opening game when she broke Ostapenko, Williams was nowhere near her best in the first set, before fighting back and winning the second.
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.
Williams struggled with her serve in the second set too, but went ahead 3-0 with a couple of early breaks as she started to hit more confident shots, including several crowd-pleasing double-handed passing shots. Another break in the ninth game delivered her first set of the comeback.
"In the beginning, it felt a little tough. But as the match moved on, I was less afraid. I knew I was not going to fall over and break," said Williams.
"The more I played, the more confident I felt that I would be able to go for shots that I was afraid to go for in the first set."
In the super tiebreaker, Ostapenko raced to an 8-2 lead before quelling a brief recovery by Williams.
Williams said she was delighted with the way she competed.
"For me, it is all about physical, how I am feeling physically ... I am just proud being out here and playing in Abu Dhabi and to be able to just compete. I have had a tough few months and I am just excited to be able to play again."
It was the first time a women's match had been played in the traditionally men's only exhibition event.
US Open runner-up Kevin Anderson defeated Spain's Roberto Bautista Agut 6-4, 7-6 (0) in the men's final. The 14th-ranked Anderson immediately broke Bautista Agut and was never in danger of losing serve in the first set.
In the second set, Bautista Agut broke in the second game, but the South African broke back immediately. An aggressive Anderson swept the tiebreaker.