The 18-year-old made his tenth Chelsea appearance as they secured a much-needed away win over Legia Warsaw in the first-leg of the Europa Conference League.
Fellow youngster Tyrique George opened the scoring with his first senior goal before Noni Madueke secured the win with a brace.
Maresca was full of praise for his whole side following their ‘professional win’ but singled out Acheampong.
“The one I fall in love with tonight is Josh Acheampong,” Maresca said. “He can be a fantastic player for this club.
“He is a good player, can play in different positions, and he showed that. Since we started, I'm in love with him but tonight he showed he can be a very good player for this club.
“He can be good in different positions. The best thing for Josh is that he's open — he wants to learn. ‘Full-back? No problem, what do I have to do’?”