German tennis is facing a bleak future after the national team was knocked out of the Davis Cup's elite World Group for the first time in 20 years, former winners of the competition said on Monday.

"We've got to where we belong at the moment," said former Davis Cup captain and Wimbledon champion Michael Stich, who spearheaded the last Germany victory in 1993. "It will be no cakewalk to get out from down there now."

Prior to their 3-2 defeat by Belarus on Sunday, Germany, who also won the competition in 1988 and 1989, had not dropped out of the 16-team elite since being promoted in 1983.

"It's not just a little accident. It's a catastrophe for German tennis," said Carl-Uwe Steeb, who was a member of all three of Germany's winning teams.

The German game has been struggling to replace the golden generation of stars it had in the 1980s and 1990s when Stich joined Boris Becker and Steffi Graf in winning a swathe of major titles around the world as well as the string of Davis Cup wins.

Tommy Haas, arguably their best singles player, is still struggling to recover from a shoulder injury.

Steeb was particularly critical of Rainer Schuettler's preparation for the match which sealed Germany's exit when he lost to Max Mirnyi 6-3, 7-5, 6-3.

"Rainer's preparation for the most important Davis Cup match in years was completely amateurish," Steeb said. "The week before he was playing on hard courts in Brazil in 40 degree heat. You just can't have that."

Germany had opted to play the tie with Mirnyi on clay, knowing that it was his least favourite surface but the tactic failed to hinder the towering Belarussian.

He won both his singles matches as well as teaming up with Vladimir Voltchkov to beat Schuettler and Nicholas Kiefer in Saturday's doubles.