Li crushed second seed Sharapova at Rod Laver Arena, overpowering the in-form Russian in a breathtaking display of power hitting to set up her second title shot at Melbourne Park against defending champion Victoria Azarenka.
Two years ago, Li was in the box seat to beat Clijsters after taking the first set, but crumbled under the pressure and took her frustrations out on Chinese fans.
"(In) 2011, (the) first time to the grand slam final, I was a little bit shocked because I didn't know what I should do," Li said.
"Also no one told me what I should do on the court. But this time I've got more experience, so I think I should be better."
The stinging loss to Clijsters spurred Li to win her sole major title at Roland Garros a few months later, but the 30-year-old Chinese had endured more than 18 months in the grand slam wilderness until her stunning revival in Melbourne.
Much of Li's struggles have been between the ears, struggling to deal with the heightened expectations from her home country of 1.3 billion people, but few nerves were on display as the sixth seed demolished Sharapova in one hour and 33 minutes in 34 Celsius (93F) heat.
Sharapova had charged into the semi-final like a freight train, conceding only nine games in the tournament and bullying a succession of weaker opponents.
But Li quickly took the wind out of her sails, breaking Sharapova three times to wrap up the first set, then weathered a fierce challenge on her own serve in the second before coolly closing out the second match-point when the Russian found the net.
Four-times grand slam champion Sharapova finished with 17 winners and 32 unforced errors, and with her tactic of attacking Li's forehand failing to come off, threw frustrated glances at her Swedish coach Thomas Hogstedt, former mentor to Li.
"I think she played a really great match. She was certainly much more aggressive than I was, dictating the play. I was always on the defence," Sharapova said.
"There's no reason why she can't win (the title)."
Keeping Sharapova pinned to the baseline and jumping on her second serve, Li raced to a 4-1 lead courtesy of an imperious backhand down the line on the third break-point of the game.
Li marched on to raise three set points, closing it out in style by blasting a cross-court forehand that kissed the line.
Sharapova went for broke and was awarded a breakpoint at 1-0, but the Chinese showed nerves of steel, saving it with a cross-court forehand winner that grazed the line.
Li pressed again at 2-2, with Sharapova conceding a second break point in the game with her fifth double-fault and then smacking a backhand long to fall behind 3-2.
Li ripped three huge serves to stave off a breakpoint in the following game, enjoying a rush of confidence that she rode to victory.
Within two hours of victory, Li's success had generated 14 million hits on Weibo, China's Twitter-like microblogging platform.
"Li Na, you were so good today you're easily going to take the crown," wrote one Weibo user.
Li's 2011 French Open triumph was watched by a television audience of 116 million in China, a domestic record for a sporting event that year.
"I'm not a better player than I was (in France), but I'm more mature," said Li. "I understand better how to adjust during the match, and know better how to control myself."