Thiago netted a first-half hat trick for the Spaniards before Malaga star Isco added a fourth from the penalty spot midway through the second half, with Ciro Immobile and Fabio Borini's goals 10 minutes from the start and end of the match, respectively unable to impact the result.
Verratti, who played 75 minutes of the showpiece, believes La Rojita - who were defending their title - are deserved victors of the tournament.
"It was always going to be a difficult game, but we knew that right from the start," Verratti told Rai Sport. "We took to the field with a desire to win, but unfortunately did not succeed.
"Spain were superior to us and we must congratulate them."
Italy Under-21 coach Devis Mangia went on to praise his team for its efforts throughout the tournament and believes inexperience is the reason why it fell at the final hurdle.
"I had to thank the lads and the staff. They achieved something important and I hope everyone can recognize their merits," Mangia said. "The only flaw today was inexperience and that was not their fault. It can only arrive with playing time at the top level and experience.
"I must compliment the team, as not many would've tried to stay in the game right to the end with that result."
Spain collected its fourth title following the victory, but Italy still boasts the highest number of European Under-21 Championships with five.