Sydney, Australia, 13 January 2013 | AAP

Feeling “unstoppable” after capturing his breakthrough ATP title, Bernard Tomic believes anything is possible in the Australian Open.

The Queenslander continued his remarkable transformation with a gutsy 6-4 6-7(2) 6-3 win over South African Kevin Anderson at the Sydney International on Saturday night in his first ATP final.

It completed a marvellous day for Australian tennis, after Lleyton Hewitt had earlier secured the Kooyong Classic in Melbourne.

It was his eighth straight win and along the way Tomic shocked world No.1 Novak Djokovic, Tommy Haas (20) and Andreas Seppi (22) at the Hopman Cup in Perth, before beating higher-ranked players Marinko Matosevic (47), Florian Mayer (26), Seppi and Anderson (36) in Sydney.

Tomic will begin his Open campaign on Tuesday against Argentina’s Leonardo Mayer with a possible third round showdown with Roger Federer awaiting.

But he has no fear and says there are no limits on what he can achieve.

“Anything [is possible],” Tomic said.

“I’ve got a good opponent in the first round and I’m playing great tennis. Who knows from there?

“I feel unstoppable. I feel I’m playing great tennis.

“When you know no-one can beat you, not to even the No.1, you’ve got a good feeling and it’s amazing stepping on court.

“That’s going to be taken down to Melbourne I’m going to use that for every match I play there and try do the best as I can.”

He will enter the tournament with a ranking improved by more than 20 places, possibly as high as No.43, reclaiming the Australian No.1 honour from Matosevic.

He became the ninth Australian winner of the Sydney event, the first since Hewitt in 2005, and becomes the first 20-year-old to hoist the trophy since Federer in 2002.

With the legendary Ken Rosewall watching on, Tomic showed little signs of nerves as he began strongly against big-serving Anderson.

Tomic broke the towering South African’s serve in the second game, racing to a 3-0 lead, and served well at crucial times to seal the first set in just 27 minutes.

He was made to work much harder in the second set, as Anderson reeled off three consecutive service games without conceding a point.

Tomic kept his cool, defusing a break point trailing 4-3, but Anderson was always in control of the tiebreak, winning it 7-2 to level.

The Australian failed to convert any of three break points in the fourth game of the deciding set by finally converted his seventh of the set when Anderson double-faulted to give Tomic a 5-3 lead.

He closed out comfortably and dropped to kiss the blue court in celebration.

“I know now what it feels like to win a tournament, it’s the best feeling in the world,” Tomic said.

“But I can’t stop here now I’ve got to look to the next tournament and keep playing the tennis I’ve been playing.”

He heads to Melbourne with a fresh wave of support and many new admirers following a controversial end to 2012, having slipped from a career-high ranking of 27 and facing criticism over his attitude and off-court behaviour.