Second seed Nicolas Almagro made an early exit from the ATP Brazil Open as he was beaten in the second round by Argentina's Federico Delbonis.
Almagro was granted a bye into the last 16, but advanced no further as his 23-year-old left-handed opponent fought back from a set down to beat him 3-6 6-3 6-2 on the clay in Sao Paulo.
The Spaniard looked to be on course for the quarter-finals as he claimed the only break of the opening set to move ahead.
But a tenacious Delbonis fought off seven more break-point opportunities for his rival in the second and pounced with his only chance on the Almagro delivery to level the match.
That seemed to knock the stuffing out of Almagro and Delbonis claimed two more breaks in the decider to complete an excellent victory.
Delbonis now faces another Spaniard, Albert Montanes, who progressed when Brazilian wildcard Joao Souza pulled out when 3-2 ahead in the second set having lost the first 6-4.
Top seed Tommy Haas claimed a 7-6 (7/2) 6-3 win over Italy's Potito Starace to book his place in the quarter-finals.
Neither player could make an impression on the other's serve in the opening set, which the German took on a tie-break. In the second, Haas began to assert his superiority against a player ranked 140 places beneath him and broke twice to ease into the last eight.
Elsewhere, Argentine duo Horacio Zeballos and Guido Pella went head-to-head for a place in the last eight and it was the former who progressed after claiming a 6-3 6-4 triumph.