Belgrade: Ricardo Mello of Brazil upset last year's finalist John Isner of the United States 6-4, 7-6 (4) on Tuesday in the first round of the Serbia Open, while former fifth-ranked Fernando Gonzalez of Chile made a winning return from an eight-month injury layoff.
The big-serving Isner had 18 aces but Mello converted the only break point of the first set to take control of the match. The Brazilian then saved four of the five break points he faced in the second before prevailing in the tiebreaker.
Gonzalez beat qualifier Martin Klizan of Slovakia 6-2, 6-4 after recovering from hip surgery. The 30-year-old Gonzalez dominated the first set, although both players struggled to hold serve in the second. Klizan double-faulted on Gonzalez's second match point.