Bernard Tomic plays a forehand during his match against Poland's Lukasz Kubot.

Bernard Tomic plays a forehand during his match against Poland's Lukasz Kubot. Photo: Getty Images

Australia's six-year stint in the Davis Cup wilderness is over after Bernard Tomic secured victory against Poland and a long-awaited return to the top-tier World Group.

Tomic defeated Lukasz Kubot 6-4, 7-6 (7-5), 6-3 in Warsaw on Sunday to give Australia an unassailable 3-1 lead in the best-of-five World Group playoff tie on clay.

It was Tomic's second singles victory in the tie, after he and Lleyton Hewitt gave Pat Rafter's side a 2-0 lead on the opening day with straight sets wins.

Poland kept the tie alive as Marcin Matkowski and Mariusz Fyrstenberg defeated teenage debutant Nick Kyrgios and Chris Guccione in Saturday's doubles before Tomic finished the job in impressive fashion.

The victory means Australia, 28-times Davis Cup champions, will return to the top 16 next year for the first time since 2007.

Australia had reached the World Group playoffs for the past three years, only to fall at the last hurdle.

But it was always in control against a Polish side depleted by the significant loss of world No.14 Jerzy Janowicz to a back injury.

Top-ranked Australian Tomic improved his record in Davis Cup singles to 12-2 with wins over world No.70 Kubot and 113th-ranked Michal Przysiezny.

The 20-year-old also won both of his singles rubbers on clay against Uzbekistan in April to seal progression to the playoffs.

While Tomic's attitude has come under fire several times in his career, he showed genuine fight against Kubot on Sunday, coming back from 5-1 down to win the second set.

After taking the first set with a controlled performance, Tomic surrendered momentum as he was broken twice and Kubot lifted the home support at Warsaw's Torwar Hall.

But the Australian world No.51 dug deep.

He won four straight games to level at 5-5 before prevailing in a tight tiebreaker, letting out a passionate scream as he converted his first set point with a winner down the line.

The comeback broke Kubot's spirit and Tomic closed out the match comfortably before embracing captain Pat Rafter and his Australian teammates.

Australia was close to wrapping up the tie inside two days with Kyrgios and Guccione falling in a five-set thriller on Saturday.

Rafter handed 18-year-old Kyrgios a surprise debut in a tactical move to keep 32-year-old Hewitt fresh for the final day.

However Tomic ensured Hewitt's scheduled match against Przysiezny would not be needed as a deciding rubber.

AAP