Nicky Clark, Pavol Safranko, Fraser Aird (penalty) and Craig Curran were all on target for Robbie Neilson's men, with Alan Trouten (penalty) and Iain Flannigan scoring for Jim Goodwin's team.
United are now just three points behind leaders Ayr United, who they face at Tannadice on Friday November 30, live on BBC ALBA.
