NICE, France -- Top-seeded John Isner of the United States lost 6-4, 5-7, 7-6 (6) to Federico Delbonis of Argentina in the Open de Nice quarterfinals as both players wasted match points on Thursday.
Isner, who rescued a match point in the second set, served for the match in the deciding set but was broken. He went on to save two more match points in the tiebreaker, before eventually succumbing to the seventh-seeded Delbonis.
Delbonis will face home favorite Gilles Simon in the semifinals after the fourth seed eased past another Argentine, Carlos Berlocq, 6-4, 6-1.
Second seed Ernests Gulbis of Latvia and defending champion Albert Montanes of Spain struggled at times before winning their respective matches.
Gulbis beat fifth-seeded Dmitry Tursunov of Russia 6-3, 3-6, 7-6 (5), while Montanes defeated Argentine qualifier Leonardo Mayer 6-7 (6), 6-4, 6-4.