Rusedski, trying to regain some confidence before Britain's Davis Cup tie with South Africa, lost to the Belgian-born Italian 6-3, 6-4 in the high altitude of Uzbekistan.
"I never got used to the conditions," said Rusedski, who was attempting to win the title his fellow Briton Tim Henman claimed last year. "He [Tieleman] has been here three times before and adjusted well."
Rusedski, world No 7 in the latest ATP rankings, is confident that he will be ready to face the South Africans as Great Britain attempt to maintain their place in the World Group.
"I've been pleased with my recent form," he said. "This is just one of those games you've got to forget. It was tough after a Grand Slam to come over here.
n The centre court used for the German Open women's tournament in Berlin will be named Steffi Graf Stadium in tribute to the former world No 1 who retired this year. Graf won the German Open nine times.Reuse content