Riba prevailed over the Slovakian Blaz Rola, seeded number eight in the tournament, scoring 7-5, 5-7, and 6-2 during nearly two hours on the court.
An ace in the first set gave the Barcelona native an edge over his opponent, breaking the serve when the match was 5-5.
Rola had his shot at a rematch in the second set, playing off of the Spaniard's repeated returns into the net.
The third and final set was all for Riba, who improved his return hits and knew how to take advantage of the Slovakian's mistakes.
Riba went out onto the clay to celebrate, cheered on by the audience.
"I'm happy about the triumph and want to just enjoy it right now. I felt at home," said the champion.
"Riba was excellent and beat me," Rola admitted about the Spaniard, who scored 80 points higher in the classification of professional tennis players.
Photos: Benicio González