Duffy, 20, was called into the first XI following a string of injuries, and Moyes believes that his performance was a highlight in an otherwise disappointing display.
"I thought Shane Duffy was our best player, I thought he was excellent," claimed Moyes. "The boy should take a lot of confidence from his performance and he certainly didn't let anybody down today.
"We're pleased with the lad. It's never easy. I think it's a difficult thing for a young centre-half to play in the Premier League.
"I think it's the hardest position now with the quality of the centre-forwards. There's less and less young centre-halves starting games in the Premier League so he's done very, very well."
Duffy was recalled from a loan spell with Scunthorpe earlier this month after injuries to Sylvain Distin and Phil Jagielka.