John Isner's poor end-of-season form continued at the Valencia Open Wednesday as the big-serving American lost 7-6 (2), 4-6, 6-4 to David Goffin in the second round.
The American player hit 21 aces but it wasn't enough against his Belgian opponent, who is enjoying an impressive season in which he is climbing the rankings. Goffin started the year at No. 175 and is currently ranked 45th.
Isner has gone 4-5 since winning in Winston-Salem in August, and will find his bid to qualify for the World Tour Finals next month severely limited with only the Paris Masters left to play before the season-ending event.
Reigning champion Marcel Granollers of Spain also beat Czech qualifier Jan Hajek 7-5, 6-4 to advance to the second round.