Horacio Zeballos denied Rafael Nadal a fairytale finish to his comeback tournament on Sunday, rallying to hand the Spaniard a rare clay court defeat in the $410,200 ATP event here.
Zeballos, ranked 73rd in the world and playing in just his second ATP Tour final, rallied to beat the former world number one 6-7 (2/7), 7-6 (8/6), 6-4.
He became just the third player -- along with Novak Djokovic and Roger Federer -- to beat Nadal in a clay court final, quite an achievement for the Argentinian despite the fact that Nadal was playing his first tournament in seven months.
Nadal was back in action this week for the first time since a surprise second-round exit at Wimbledon in June.
Since then he had been sidelined by a torn tendon and inflammation in his left knee, with his return this year further delayed by a virus.
Now ranked fifth in the world, 11-time Grand Slam champion Nadal was the top seed and had lost just 15 games en route to the final.
Neither player managed a break of serve in the first two sets. They traded breaks in the first two games of the third before Zeballos broke Nadal at love in the final game of the match.
Nadal was scheduled to return to the court later teaming with Argentina's Juan Monaco in the doubles final against Italians Paolo Lorenzi and Potito Starace.
The 26-year-old had played down his expectations coming into the week, saying he still felt some pain in the knee and just wanted to get in as many matches as possible to regian his sharpness.
He plans to compete in clay court events in Brazil and Mexico before playing ATP Masters hard court events at Indian Wells and Miami and then heading to Europe for clay events in Monte Carlo, Barcelona and Rome ahead of the French Open.