"Yeah. You know, definitely. Two (matches) is plenty for me, for sure," she said.
Williams, who describes herself as lazy and uninterested in sports and anything athletic, has floated above the rat-race for years in a sport dominated by egos, entourages and head doctors, never seriously getting out of bed for anything but the majors.
Once on center court, however, the fires still burn after a long and storied career featuring three U.S. Open titles, four Wimbledon crowns and the 2002 French Open since turning pro in 1995.
"I get the same burst, if not more. I love playing majors and I love competing," Williams said.
"More than anything, I hate losing. That kind of makes me really hungry to work harder to get the results that I want."
After her long lay-off, the former world number one is seeded 12th at Melbourne. She faces an unheralded Austrian in the first round and no-one appears capable of troubling her in the opening week. A potential quarter-final looms with world number four Maria Sharapova.
Her ankle is also coming good and she felt no great discomfort after putting it through its first major test on Saturday, though she would wait to see how it responds.
Tough opening round for Sania in Aus OpenThe rest of her appears in ominously good condition.
Conversely for a woman who decries exercise, local newspapers have delighted in touting a leaner, meaner Serena, splashing pictures of the American's washboard stomach on their websites.
Mentally she is relaxed as ever, finding time to engage in a Twitter dialogue with fans in between hit-ups at Rod Laver Arena and icing her sore ankle.
Her face falls only momentarily when she ponders a tournament without her older sister and doubles partner Venus, who pulled out of Melbourne amid her battle with Sjogren's syndrome, an auto-immune illness.
Long-time friend and verbal sparring partner Andy Roddick has been drafted in to cheer Williams by teaming up with her in the mixed doubles.
"I think it will be really fun. I hit the worst volley today, and I was a little worried," Williams said. "I was like, 'he might want to get a new partner.' We'll see how it goes.
"I am (in it to win it). He'd better be."