Tony Watt came back to haunt former employer St Johnstone and clinch all three points for Dundee United.
The striker found the back of the net with little under 10 minutes remaining following what had been a rather monotonous encounter until that point.
It proved to be the only goal of the contest and resulted in Saints dropping out of the top six, with their second-from-bottom Tayside rivals closing the gap to five points.
