Bernard Tomic has provided Australia with an ideal start to their Davis Cup tie against Germany by overcoming Cedrik-Marcel Stebe in bone-chilling conditions in Hamburg.

After making a sluggish start against the tricky left-hander, world No.42 Tomic won 2-6 6-3 6-4 7-6 (7-4) in three hours and 17 minutes on clay at Rothenbaum Stadium.

So cold was it courtside that Davis Cup captain Pat Rafter sat with a towel around his neck to keep warm.

The victory in testing, breezy conditions over the world No.127 was just what the Australian teenager needed following his controversial US Open flop a fortnight ago that Rafter described as "disgraceful".

The unforced error count was high with Stebe, playing in his first live Davis Cup rubber, committing 80 to Tomic's 70 under grey skies.

Australia must win the tie to return to the elite World Group next year for the first time since 2007.

Tomic won the opening six points before 21-year-old Stebe composed himself and the tall Australian became frustrated having to play extra shots on the slow surface.

Errors flowed from Tomic's racquet as he surrendered the opening set.

The Australian adjusted to the conditions and started pushing his opponent around to take the second set and carried that momentum into the third set.

He continued to chip away at Stebe's serve as he grabbed a two-sets-to-one lead.

The young German jumped out to a 3-0 lead in the fourth set before Tomic fought his way back and had a chance to serve for the match at 5-4.

At 30-30, Tomic made two errors with the set had to be decided in a tie break.

Lleyton Hewitt will take on German No.1 Florian Mayer in the second singles rubber shortly.

Hewitt and Chris Guccione will play in the doubles rubber against Germany's Philipp Petzschner and Benjamin Becker on Saturday before the reverse singles on Sunday.

Tomic was relieved to have grabbed the win with light rain falling late in the contest and the roof being closed for the second singles rubber.

"I am really, really happy," he said.

"It was not a good feeling being down a set.

"I had been training all week and I had been hitting the ball the best I have ever done.

"To be down a set after that to a guy that is playing really, really good tennis is a difficult feeling.

"But I managed to find my way out of it."