The top-seeded Haas suffered a stunning 6-4, 6-4 loss to American teenage qualifier Alex Bogomolov Jr. on Tuesday night in the first round of the $375,000 Mercedes-Benz Cup.
Haas was playing for the first time since the French Open. He spent some time with his parents in Florida and native Germany while they were recovering from serious injuries suffered in a motorbike accident.
Clearly rusty, Haas never found a rhythm against Bogomolov, a 19-year-old from Miami ranked 278th in the world who has won three titles on the Futures circuit.
Haas had his serve broken in the ninth game of the first set. Bogomolov scored a pair of breaks to take a 4-1 lead in the second set before Haas battled back within 5-4. In the final game, he wasted a pair of chances to win before netting a backhand service return.
"I'm feeling incredible," Bogomolov said. "I've been waiting for this moment for a long time, maybe most of my life."
Haas' early exit from the tournament that begins the American hardcourt season leading to the U.S. Open clears the way for a number of players, including Andre Agassi.
The defending champion and second seed, Agassi routed Kenneth Carlsen of Denmark, 6-3, 6-1, in the first round. The 32-year-old Las Vegas native won here in 1998 and last year, when he defeated fellow American Pete Sampras.
Unheralded Noam Okun of Israel surprised No. 6 Sjeng Schalken of the Netherlands with a 7-6 (7-5), 7-6 (7-4) victory. Okun avenged a 1999 loss to Schalken on a hard court at Indianapolis.
No. 3 Sebastien Grosjean of France tried to jump-start his game with a 6-1, 6-2 victory over American qualifier Jack Brasington.
Fifth-seeded Gustavo Kuerten of Brazil also advanced with a 7-5, 7-6 (9-7) win over Swiss star George Bastl in his opening match. Kuerten lost to Agassi in the semifinals here last year.
Bastl made a name for himself by knocking out Sampras in the second round of Wimbledon.
No. 7 Xavier Malisse of Belgium got past qualifier Scott Draper of Australia, 6-4, 7-6 (7-4). Malisse lost in three sets to Sampras in last year's semifinals. Draper was a quarterfinalist
here in 1996.
No. 8 Max Mirnyi of Belarus finally broke through against Cecil Mamiit of the United States with a 6-4, 6-4 victory. Mamiit had won the first three meetings, including a first-round victory at the French Open.
Americans went 2-2 in matchups of unseeded players. Brian Vahaly defeated Davide Sanguinetti of Italy, 6-3, 6-1, and Robby Ginepri eliminated Harel Levy of Israel, 6-3, 6-2. Vincent Spadea was beaten by Srichaphan, 7-6 (7-5), 3-6, 7-6 (7-2), and wild card Justin Gimelstob was bounced by Nicolas Kiefer of
Germany, 7-5, 6-1.
In an early match between unseeded players, Martin Lee of Britain bounced Takao Suzuki of Japan, 6-4, 7-5.