"I am just very amazed I coped with the pressure today," Djokovic said. "In the most important moments, I played my best tennis."
"It's just amazing, indescribable, to beat the No. 1 player of the world, one of the best players this sport has ever had, in straight sets."
He will face unseeded Jo-Wilfried Tsonga in Sunday's final. Tsonga beat No. 2 Rafael Nadal in the semifinals Thursday.
In the women's final Saturday another Serbian, fourth-seeded Ana Ivanovic, will meet No. 5 Maria Sharapova.
Other than a twitchy third-round victory over Janko Tipsarevic that went to 10-8 in the fifth set, Federer has been in good form after a stomach ailment interrupted his pre-tournament preparations. He dominated James Blake in the quarterfinals and appeared to be peaking at the right time.
Instead, he fell to his first straight-sets loss in a Grand Slam tournament since a third-round defeat to Gustavo Kuerten at the 2004 French Open.
"I think he made the more important points today, it was a bit unfortunate for me," said Federer, who rubbed his eyes frequently at his post-match news conference. "You can't always play your best. There is no doubt I have played better before.
"I've created a monster that I need to win every tournament - still the semifinals isn't bad."
Despite a 1-5 record against Federer that included a loss in the U.S. Open final in September, Djokovic was far from intimidated on a muggy night in a packed Rod Laver Arena, even after getting broken in the first set.
Federer, who is usually at his best as the pressure builds toward the end of a set, pulled ahead at 5-3 only to be stunned as Djokovic ran off the last four games, with the Swiss star hitting backhands long on the last two points of the set.
Federer grimaced or hung his head as his groundstrokes and feathery drop shots lacked their usual punch and accuracy, or deserted him entirely.
"He covered the court well," Federer said. "I couldn't come up with the passing shot when I needed to.
"There is some sort of a disappointment. The way I tried, that's all I could give. When you give 100 percent, you're sort of happy with your performance. It can't always go your way."
Djokovic broke him to pull ahead at 3-1 in the second set. He finished off the game by getting to a drop shot on the dead run and flicking a backhand past Federer that kissed the line. Djokovic roared and raised his fist, then repeatedly pounded his chest.
He broke again to pull ahead at 5-1. Serving for the set, Djokovic looked a little tight, and Federer took advantage to break. When he held to make it 5-3, the crowd erupted into chants of "Let's go Roger, let's go" that nearly drowned out shouts of "No-vak, No-vak."
"I felt the crowd was not behind me, but that's OK ... I fight two opponents," Djokovic said.
Federer forced deuce as Djokovic served again for the set. Known for his tendency to bounce the ball up to two dozen times before serving, the Serbian got a time delay warning. Instead of being shaken, Djokovic was fired up. He ripped a forehand winner and glared up at chair umpire Pascal Maria of France, then blasted an ace and stared defiantly at Maria again.
The two men combined to fend off seven break points early in the third set. Federer had two chances to break as Djokovic served at 5-6, but the Serbian refused to crack, hitting two great serves, then getting to a drop for a forehand crosscourt winner to force a tiebreaker.
From 3-3, the two players combined for five straight winners, the last a good serve by Djokovic that set up match point. Federer netted a forehand to finish it in 2 hours and 48 minutes.
The crowd slowly rose to its feet, almost in disbelief, before applauding Djokovic, then gave Federer a standing ovation as he quickly left the court.
