Partick Thistle recorded their first home win in the league and more importantly opened a three-point gap between themselves and fellow strugglers Motherwell, who now prop up the division.
Gaols by Martin Hardie and Alex Burns proved the difference between the sides and there was no way back for Well when Scott Leach was ordered off 19 minutes from time for a second yellow card.
The home side were first to threaten when Hardie's looping header was held by Steve Woods under the bar.
The visitors then went close when Steven Pearson latched on to Woods' clearance before firing in a shot which Kenny Arthur saved well.
When Martyn Corrigan miscued his header Hardie was first to react but Woods did well to block his header, while James McFadden looked in the mood for the visitors but lacked support.
Gerry Briton's snap-shot on the turn went narrowly over before the home side took the lead on the half-hour mark. Hardie won the corner and when Burns' cross came in Hardie leapt high at the back post before powering his header home.
It was a deserved breakthrough for Thistle and Woods had to look sharp to cut out Alan Archibald 's dangerous cross. Motherwell began to loose their discipline with Pearson and McFadden booked in the space of a few minutes.
Thistle went two ahead shortly after the break, when Burns stroked the ball home from the edge of the box after Scot McLean had created the chance.
Motherwell responded by sending on Dirk Lehmann for Daniel Sengewald in attempt to boost their attack and the German striker went close with a header form a McFadden cross.
McFadden then had a shot blocked, but the ordering off of Leitch after the Motherwell midfielder took a wild swing at Hardie ended any chances the visitors had of scoring