Félix Auger-Aliassime's chance to tune up for the upcoming French Open came to an end Wednesday with a 4-6, 7-5, 6-4 loss to American lucky loser Aleksandar Kovacevic.
Montreal's Auger-Aliassime, seeded first at the ATP 500 clay-court event, had a 4-1 lead in the deciding set before Kovacevic mounted an improbable comeback.
Auger-Aliassime had won his previous two matches against Kovacevic.
Kovacevic, who was initially eliminated in qualifying before getting a main-draw spot when Zizou Bergs withdrew, is the first American to reach the Hamburg quarterfinals since Andre Agassi and Pete Sampras in 1995.
Auger-Aliassime, ranked No. 5 in the world, saw his record this season fall to 19-10 as he was eliminated in the second round at a second straight tournament.
The Canadian star will look to regroup at Roland Garros, where he has been eliminated in the first round in two of his last three appearances.
