The 23-year-old, who found the back of the net in Chelsea's 2-0 win over the Italian outfit in a pre-season friendly, arrived at Stamford Bridge from Bayer Leverkusen this summer.
"I'm really happy to have scored my first goal, it's pre-season but it always feels good to score," he told the club's official website.
"It was my first for Chelsea so it was a really nice day for me. It's gone very well, we've played five games and won five games."
Chelsea open their Premier League campaign at home to Hull City on August 18.