* (Updates with federation quotes, details, background)
BERLIN Oct 31 (Reuters) - German Davis Cup captain Patrik Kuehnen will step down at the end of the year after a decade in charge following what he said was a lack of support from the federation during a year marred by infighting and bad results.
Kuehnen has been locked in a bitter row for months with world number 19 and Germany number one Philipp Kohlschreiber, who has ruled out a return for the team's first tie in 2013 against Argentina.
"In the past weeks I got the impression that I was missing the necessary support and backing from the German tennis federation (DTB)," Kuehnen said in a statement.
"So I have no basis of trust to continue working together and I end at this point the talks for continuing my work at the DTB," added the 46-year-old.
Kohlschreiber accused Kuehnen of failing to support him after former world number two Tommy Haas had questioned his commitment in February when he missed the first round 4-1 defeat against Argentina with a stomach bug.
The row had drawn in other former and current players with Kuehnen, who won the Davis Cup three times as a player, unable to resolve it.
Kuehnen did not pick Kohlschreiber for their most recent tie, a 3-2 World Group playoff win over Australia in September.
"His decision is no surprise because in many talks with Patrik Kuehnen and the players it became evident that a new start would be the best solution for men's tennis," said DTB boss Karl Altenburg.
The federation has said it hopes to find a replacement before the end of the year.
Tennis has largely dropped off the radar for German fans since the glory days of Boris Becker and Steffi Graf in the 1980s and 1990s. (Reporting by Karolos Grohmann, Editing by Tom Pilcher)