Second seed Federer, third seed Nadal and sixth seed Andy Murray all enjoyed straight sets wins, with rising stars Simona Halep, Eugenie Bouchard and Grigor Dimitrov also progressing on a cool Melbourne day.
World number two Sharapova, looking for her first Australian title since 2008, swept aside Croat Petra Martic 6-4, 6-1.
"I made a few too many unforced errors but overall I'm glad I got through," said the Russian, adding that she was reaping the benefits of a strong lead up to the tournament when she won the Brisbane International.
She started well against unheralded world number 142 Lucie Hradecka of the Czech Republic, easily winning the first set, but then went to pieces, eventually crashing 1-6, 6-3, 6-2.
Also Read
"I really struggled to find my rhythm today, I was just a little bit lost," said the stunned Serb, a perennial crowd favourite in Australia where she has family.
Ninth seeded German Angelique Kerber also failed to live up to the hype, eliminated in three sets by Romanian Irina-Camelia Begu.
He went through the motions for a 6-4, 6-2, 7-5 win and welcomed the workout.
"It's early in the season and it's tough to get rhythm, especially in the first round, but this court plays nice and we had some great rallies so it was a nice match," said Federer.
His long-time rival Nadal showed few signs of the injuries that disrupted his 2014 season in dispatching Russian Mikhail Youzhny 6-3, 6-2, 6-2, conceding just one break point on his serve.
"It was a comfortable victory that give me some confidence," added the Spanish 14-time Grand Slam champion.