The 20-year-old put the Lupi 2-0 up after just 24 minutes at the Stadio Olimpico, but the Bianconeri staged a comeback to win the Serie A clash 3-2.
"We are angry," he told La Gazzetta dello Sport. "I don't understand the reasons for this defeat.
"In the future, we must continue to work with the right spirit. We are working hard in training during the week.
"It's very strange that on the pitch we are not producing the right results."
Roma are currently sixth in the Serie A table with 14 points from nine matches.