MELBOURNE, Australia (AP) At the time, she called herself ''Super Serena'' and posted a picture of herself dressed like Superwoman.
In hindsight, tennis star Serena Williams thinks it wasn't the best idea to chase after a man who appeared to be stealing her cell phone.
''Sometimes, athletes just react,'' the No. 1-ranked player said Monday as she started her bid for a seventh Australian Open title with a 6-4, 7-5 win over Italy's Camila Giorgi.
Williams hadn't completed a competitive match since losing in the U.S. Open semifinals, a defeat that ended her bid to win all four Grand Slams in the same season. The last player to do it was Steffi Graf in 1988.
The extended break raised questions about Williams' form and meant she hadn't elaborated much publicly on the cell phone incident, which happened in November while she dined with a friend at a San Francisco restaurant. She wrote about it in a Facebook post at the time, saying she had noticed a man lurking near her table before he grabbed the cell phone and left.
Surveillance footage showed Williams quickly leaving the restaurant and appearing to confront the man on the sidewalk. Williams wrote that she asked the man if he had accidentally taken the wrong phone, and he gave it back. She signed the post, ''Super Serena'' and the tale quickly made headlines.
''I didn't think it would be such a big story,'' Williams said Monday. ''I didn't know it would be everywhere, every blog, every TV channel and every radio station. People were calling me. My dad was worried. I just had no idea it would blow up like that.''
Asked if she would do it again, Williams said, ''Oh, God, no. I reacted and I didn't think.''
Now, her focus has returned to tennis and the 21-time Grand Slam winner says she's fit despite her time off and a recent injury.
''I haven't played in a long time, but I have been playing for 30 years so - I try to focus on that,'' said Williams, who withdrew from the Hopman Cup earlier this month after playing just one set because of inflammation in her left knee.
Williams said she didn't feel the knee problem at all during Monday's match, dropping just one service game against No. 34-ranked Girorgi.
No. 5 Maria Sharpova, who lost to Williams in last year's final, breezed through her first-round match 6-1, 6-3 against Nao Hibino of Japan.
Sharapova showed no lingering effects from her own recent ailment, a left forearm injury that forced her to pull out of the Brisbane International earlier this month.
''I haven't played many matches in many weeks, it was great to come out here and start my season,'' said Sharapova, a five-time Grand Slam winner who could face a rematch against Williams this year but in the quarterfinals.
In her off-court time, Sharapova said she's been working on a biography.
''I'm not going to talk about it much just because I want the book to do the talking. But I'm really excited about it,'' said Sharapova, who said she has been interviewing her mother, father and grandparents and plans to include some journals she kept as a young girl. Digging up her past, she said, has been ''really interesting and scary at the same time.''
Williams, who has an 11-year dominance over Sharapova, is the favorite in Melbourne but faces a strong crop of resurgent and determined players.
Among them is 2014 Wimbledon finalist Eugenie Bouchard, who continued an injury comeback Monday beating Aleksandra Krunic of Serbia 6-3, 6-4. Bouchard faces No. 4 Agnieszka Radwanska in the second round.
Bouchard is playing in only her fourth tournament since sustaining a concussion when she fell in the dressing room at last year's U.S. Open. The 21-year-old Canadian made it to the quarterfinals at an event in China and followed that up by reaching the final at the Hobart International.
Two-time Wimbledon champion Petra Kvitova also advanced Monday, beating Thai qualifier Luksika Kumkhum to avenge her upset three-set loss in the first round here in 2014.