The sixth-seeded Tillstrom, 25, received ice-pack treatment during the third set to overcome exhaustion but finally wore down Radulescu's resistance in a two-and-a half-hour duel.
''It's a dream come true," said Tillstrom, the world's 61st-ranked player who has had to wait five years for his maiden singles title after winning his first ATP Tour doubles title in 1992.
The match hinged on a controversial line call in the 10th game of the third set which saw Radulescu, who served 11 aces to Tillstrom's five, serving for the match at 5-4.
Romono Grillotti, the chair umpire from Italy, ruled in Tillstrom's favour to give the Swede a crucial break point, prompting Radulescu to hurl his racket to the ground in disgust. "I'm sorry I behaved like that," he said. "I don't know what happened to me. I was completely shattered the moment the point was overruled by chair umpire and that affected my game. It was impossible to continue after such a decision, but in my heart I have won this title."
Michael Chang, the top seed from the United States, was on the verge of victory over Australia's Patrick Rafter in the Hong Kong Open final when rain stopped play.
Chang, aiming to add to his triumphs in Memphis and Indian Wells earlier this year, was 6-3, 5-3 and held two match points when the downpour came.Reuse content