Marat Safin served a double-fault on match point to hand Taylor Dent a 7-5 6-4 victory in the fourth round of the Pacific Life Open in Indian Wells.
After taking the opening set with a decisive service break in the final game, Dent led 5-4 in the second set.
Serving and facing match point at 30-40, Safin delivered his fourth double-fault of the match to go out.
Dent said. "I'm sure Safin would love to have played much better, but I played the big points well."
Australian Open champion and fourth seed Safin, who went out in the first round of the recent Dubai Open, said: "This is the worst match I played in my entire career.
"I felt I was not there. From the beginning, I felt like it was impossible to play my game, no matter what I did.
"I couldn't do the most simple things. I couldn't really serve well, I didn't return at all. I made so many unforced errors."
Lleyton Hewitt eased into the last 16 with a straight-sets win over France's Michael Llodra.
The Australian, seeded second, held his nerve in a tight second set on his way to a 6-2 7-6 (7-3) victory, and plays France's Paul-Henri Mathieu next.
Roger Federer also strolled into round four with a 6-3 6-2 victory over Luxembourg left-hander Gilles Muller.
Seventh seed Carlos Moya earlier beat fellow Spaniard David Ferrer 6-3 6-4.
Moya will meet Fabrice Santoro in the fourth round after the Frenchman upset 24th seed Feliciano Lopez, 6-4 6-2.