By Alastair Himmer

MELBOURNE (Reuters) - A chest-thumping Novak Djokovic blasted his way past Czech Tomas Berdych 6-1 7-6 6-1 in a heavyweight clash on Tuesday to set up an Australian Open semi-final with Roger Federer.

"I have to be confident and stay positive," added Djokovic, who knocked the Swiss maestro out of last year's U.S. Open at the semi-final stage having saved two match points. "If I play well I have a chance."

The Serb third seed, Melbourne champion in 2008, caught fire early, tearing through a one-sided first set in just 36 minutes under floodlights at Rod Laver Arena.

Sixth seed Berdych dug deep to force a tiebreak in the second but a wild forehand from last year's beaten Wimbledon finalist gifted it to Djokovic 7-5, and with it a two-set lead.

Djokovic quickly went for the jugular in the third, securing a double-break for 5-1 with a drilled forehand return and finishing off Berdych with a big serve down the middle after two hours and 32 minutes.

"I didn't even have two weeks off after winning the Davis Cup with Serbia," said Djokovic. "But I've played some of my best tennis in the last couple of months."

Berdych took his loss on the chin.

"Pretty solid start to the year, finishing quarter-finals in Melbourne," he said. "I played the third (best) player in the world. It's not that you can beat him everyday."

(Editing by Martyn Herman)