Lingard is on loan from the Red Devils until the end of the season, and has found the best form of his career in the past few months.
He scored twice as the Hammers defeated Leicester City 3-2 on Sunday to go fourth in the Premier League.
Asked about Lingard, Moyes told reporters, per football.london: "Well, he has been crucial before that. He has come in and helped the team greatly in the way he has played and also his attitude around the club, it has lifted us up.
"I didn't expect Jesse to probably get as many goals so I am really thrilled with the amount of goals he is getting at the moment and long may it continue."