After saving five break points as she adjusted to a strong cross breeze in the first game, the 15-time major winner needed less than an hour to beat No. 21-ranked Varvara Lepchenko 6-2, 6-1 in the first round of the Brisbane International on Sunday.
Williams won 31 of her last 32 matches in the second half of the 2012 season, including titles at Wimbledon, the Olympics, U.S. Open and the WTA Championships. She won 58 of 62 matches in total this year, a win-loss record she didn't want to diminish in any way.
"Tomorrow is the last day of the year, so technically I still had my 2012 rep on the line," she said. "I really needed to win today so I could finish the year with still just the four losses. So that was important for me."
Williams didn't show any signs of being hampered by the minor surgery on her big toes which forced her to withdraw from a Dec. 29 exhibition in Thailand, moving freely throughout the match against the Uzbekistan-born Lepchenko, who now represents the United States.
"I was a little nervous, but I was completely fine," the No. 3-ranked Williams said. "The doctor said I would be fine. I was excited to get an early start so just in case I did have any pain I could have tomorrow off. But everything was fine."
Williams said she didn't believe in New Year's resolutions. That doesn't stop her aiming for a sweep of the majors. She held all four Grand Slam titles at one stage, winning the 2003 Australian Open after claiming the French, Wimbledon and U.S. Open titles in 2002, but she's never completed a season slam.
"I think for me, absolutely," she replied to questions if the Slam was possible for her for 2013. "I think maybe whoever wins will Australian Open will have that same thought. I think there is no way that Victoria (Azarenka) or Maria (Sharapova) or maybe some other players don't feel the same way. So I think I definitely feel that way."
And if that doesn't work, she's planning on giving herself a few more years to attempt it, saying her experience at the London Olympics gave her the desire to keep playing until the 2016 Games in Rio.
Eight of the top 10 women are contesting the Brisbane International, with Azarenka and Sharapova getting byes in the first round.
Sixth-seeded Petra Kvitova had a 6-3, 6-4 win over Carla Suarez Navarro of Spain and will next meet Russia's Anastasia Pavlyuchenkova, who beat Lucie Hradecka of the Czech Republic 6-3, 3-6, 6-3.
Kvitova, who won the 2011 Brisbane International before claiming her first Grand Slam title at Wimbledon, was unable to convert her first match point at 5-2 in the second set, then dropped a service game before Suarez Navarro's late comeback ended with an error on the second match point.
In other matches, Australian wildcard entry Jarmila Gajdosova had a 4-6, 6-1, 6-3 win over 16th-ranked Roberta Vinci of Italy to set up a second-round match against No. 2-seeded Sharapova. Urszula Radwanska of Poland beat Tamira Paszek of Austria 2-6, 6-0, 6-2 and Slovakia's Daniela Hantuchova had a 7-5, 6-2 win over Lourdes Dominguez Lino of Spain.
Australia's Samantha Stosur was headlining the night session Monday, hoping to give the home crowd something to celebrate on Monday night.