Thistle’s long unbeaten record came to an end on Saturday with a solitary Motherwell goal at Fir Park in the 21st minute from the boot of John Sutton.
Mothewell dominated most of the first half when Sutton collected a Zaine Francis-Angol’s cross, striking the ball well to leave Scott Fox with little chance of a save.
Thistle continued to struggle with Motherwell coming closest to scoring again a short time later.
It wasn’t until the second half that Thistle came more into the game but their lack of clinical finish was to prove decisive to the scoreline.
The final Thistle chance fell to Aaron Muirhead, but he was unable to direct his header from Ross Forbes’ corner towards goal, and despite a much improved second half performance from the visitors, Motherwell held on for all three points.
Thistle have an early opportunity to get back to winning ways when Cowdenbeath visit Firhill for a League Cup second round tie on Tuesday evening.