The 42nd-ranked Vinci won her fourth career title and extended her record on the Barcelona clay to 14-1. Italian women have won three straight years in the Catalan capital, with Francesca Schiavone the champion in 2010.
"I love Barcelona," Vinci said. "I always play well here in this beautiful city."
This was the second straight match in which the sixth-seeded Vinci had to rally after dropping the first set. She broke serve six times against an unseeded opponent who committed six double-faults. Hradecka hadn't dropped a set all week in reaching the final.