The attacking midfielder hit the winner for loan club Cheltenham in their 2-1 victory at Walsall on Tuesday night in what was his first taste of senior football, having been a regular with City's Under-23s over the past few seasons.
“He'll learn a lot from that," Duff said. “It's almost a different sport to what he's used to.
“You saw what he could do with the ball. We think he can land on things, which he did for the goal.
“He's still got to learn the other side of the game. Sometimes with him and Finn (Azaz, midfield partner) in there, they vacated the middle of the pitch too much, but that's why he's here, to learn the tactical side of it.
“I thought he competed well. He didn't look like a crisp packet where he was floating around being knocked over, he competed really well."