Maria Sharapova won for the first time at Melbourne Park since taking the 2008 title, beating Thai veteran Tamarine Tanasugarn 6-1, 6-3.
Sharapova was ousted in the first round last year by fellow Russian Maria Kirilenko. "I was definitely a little bit nervous in the beginning. Last year, I played first match on center and I lost," she said.
Caroline Wozniacki started with a 6-3, 6-4 victory over Argentina's Gisela Dulko. Battling the perception that she is an unworthy world No.1 until she wins a grand slam title, Wozniacki clinched her victory after a hard-fought 100-minute contest.
"It's the first round," said the 20-year-old. "It's always tough. I'm really happy to be through to the next round."
Fifth-seeded Venus Williams advanced after beating Sara Errani of Italy 6-3, 6-2.
FedEx in a hurry
Roger Federer didn't waste any time Monday at the Australian Open, winning his opening match by playing like a man who doesn't want his remarkable 7 1/2-year run of success in Grand Slams to end.
Federer was rarely troubled in beating Lukas Lacko of Slovakia 6-1, 6-1, 6-3 in 84 minutes at Melbourne Park
Andy Roddick, too, was rarely under pressure in his 6-1, 6-2, 6-2 win Jan Hajek of the Czech Republic.
Last year quarterfinalist Nikolay Davydenko lost 6-3, 4-6, 7-6 (4), 6-4 to Florian Mayer, while Novak Djokovic tore into the second round with a 6-1 6-3 6-1 blowout of Spain's Marcel Granollers.