Ernests Gulbis produced a remarkable third-set comeback to dump third seed Sam Querrey out of Delray Beach International Tennis Championships.
With the entire second round held back a day because of rain, the American could not match the top two seeds, compatriot John Isner and Tommy Haas, in advancing to the quarter-finals.
Latvian Gulbis, who was champion in Delray Beach in 2010 but had to qualify this year, was typically erratic on his way to a 6-4 4-6 7-6 (7/4) victory.
After winning the first set, Gulbis appeared to be on his way out when he lost the second then fell 4-0 down in the third.
But, despite a point penalty for swearing, he roared back, helped by a string of errors from Querrey, to claim a notable victory.
There was no such drama for top seed Isner, who was typically dominant on serve to beat Japan's Go Soeda 7-6 (7/2) 6-2, or number two Haas of Germany, a 6-4 6-1 winner over Uzbek Denis Istomin.
Another seed to fall was number eight Xavier Malisse of Belgium, beaten 7-6 (7/3) 3-6 6-3 by Daniel Munoz-De La Nava, whose reward is a quarter-final against Gulbis.
The other men advancing to the quarter-finals were sixth seed Kevin Anderson, Edouard Roger-Vasselin, Ricardas Berankis and Ivan Dodig.
