Melbourne: John Isner branded the efforts of American men's players at the Australian Open "very disappointing" as his loss completed the worst ever US performance in Melbourne on Friday.
Providing an American has entered, there has always been at least one in the last 16 of the tournament in the open era -- highlighting the depths to which American men's tennis has plunged.
Isner's exit to Spain's Feliciano Lopez followed earlier defeats for the likes of Andy Roddick and Mardy Fish, and leaves the once-dominant nation scratching its head as to where the next hero is going to come from.
"It's very disappointing," said Isner. "That's not a good effort from the Americans this tournament. And, you know, I knew going in today I was the last one left and I wanted to keep on going, but it just didn't happen.
"But it's very ugly, to be honest, to have no one in the round of 16. We've got to try to rectify that next time the big tournaments roll."
The last American to win in Melbourne was Andre Agassi, who claimed his fourth and final Australian Open in 2003. Other US tennis greats including Pete Sampras and Jimmy Connors have also lifted the trophy.
Mardy Fish, 30, is the current top-ranked American at number eight but has never been beyond the quarter-finals at a grand slam, while former world number one Roddick, 29, is a fading force.
Isner, whose best grand slam performance is last year's US Open quarter-finals, is ranked 17th but the next American player in the rankings is 22-year-old Donald Young, at 42.