The Spaniard beat the 62nd-ranked Italian in his first tournament since January and first appearance on clay since the 2022 French Open.
Nadal's last ATP Tour match was the quarter-finals of the Brisbane International, before he pulled out of the Australian Open. He withdrew from last week's Monte-Carlo Masters saying his body was not yet ready for competition.
"I tried a lot of times in my career," Nadal said, referring to his numerous injury comebacks. "Every time it's more difficult and especially when you're at an advanced age it makes things even tougher."
"I am going through tough moments but at the same time when I am able to be on the tour for a few days and practise with the guys, and to be able to compete a little bit, it means a lot to me. Still enough enjoyable to keep doing it."
The 22-time Grand Slam champion's injuries have caused doubts about his ability to compete at the elite level again after he previously said that he expected to finish his glittering career in 2024.
Nadal is keen to play at the French Open, where he has won a record 14 titles with the latest one coming in 2022. The French Open main draw begins on May 26.
He next faces fourth seed Alex de Minaur in Barcelona, where he has won a record 12 titles and the main court is named in his honour.
