Five-times champion and sentimental favourite Andre Agassi lost in straight sets to Italian qualifier Andrea Stoppini in the Legg Mason Tennis Classic second round on Tuesday.
The 36-year-old Agassi, making his 17th and final appearance at the Washington event, had no answer to Stoppini's strong serve and crisp groundstrokes, losing 6-4, 6-3 in 62 minutes.
Stoppini, ranked 246th in the world, won his first career ATP match on Monday against Paul Goldstein before knocking out the fourth-seeded Agassi.
"I was very frustrated," Agassi, who will retire after this year's US Open, told reporters. "I wanted it really bad to get out there and be comfortable and hit my shots.
"But I felt with every point the court got smaller and smaller. I had a harder time keeping the ball in the court. I never found my rhythm."
The 26-year-old Stoppini recorded the only service break of the first set in the 10th and final game when the error-prone American punched a backhand over the baseline.
Stoppini, who had to win three matches just to qualifying for the main draw, raced into a 3-0 lead in the second set, making Agassi smash his racket on the court in disgust.
"I didn't have a plan," said a grinning Stoppini. "I just tried my best, play loose and see how it goes."
Stoppini conceded he was nervous playing before a pro-Agassi crowd on the stadium court.
"When I entered the court, the atmosphere was unbelievable," he said. "The first two or three strokes, I didn't hit it in the centre of the racket. After that, I felt better.
"I realise Agassi didn't play his best match but what could I do? That's better for me. To beat Goldstein and the Agassi is just a dream."
Agassi received a first-round bye and was playing his first match of the tournament. He said the loss throws into disarray his preparations for the US Open, which begins on August 28.
"I didn't have a good sense if I was hitting it too big or if I wasn't hitting it enough," he said. "Sometimes I pulled back when I should have been aggressive.
"Sometimes I was aggressive and I should have been more patient. It was disappointing."
The 22nd-ranked Agassi said Stoppini played well but the Las Vegas native took full responsibility for his defeat.
"I didn't even get to the point tonight where I was dealing with his game," said the eight-times Grand Slam winner. "I was trying to just make good contact, keep a few balls in play.
"I didn't do anything very well tonight."