Having been thrashed 5-1 by Kilmarnock at the weekend, the hoists were in dire need of a morale-boosting and they took the lead in the 16th minute with a stunning strike from midfielder Blair Spittal.
Carl McHugh brought down Conor Sammon at the far corner of the 18-yard box and Spittal drilled the resulting free-kick beyond the despairing dive of Russell Griffiths in the Motherwell goal.
The goal galvanised the home side and Martin Woods, making his first competitive start for seven months, then headed wide from a Miles Storey cross before the Jags doubled their advantage midway through the first half.,
Storey was once again the provider, sending Ryan Edwards through on Griffiths and the Australian drove the ball into the roof of the net from 12 yards.
Unsurprisingly, perhaps, Storey also played a key role in the third goal, although McHugh ought to have prevented his pass from reaching Sammon. When he failed to intercept, the Irishman, on loan from Hearts, was unchallenged as he stroked the ball into Griffiths’ left-hand corner.
The visitors rarely threatened, although they passed up a half-chance when, from an Elliott Frear cross, Charles Dunne’s downward header bounced over the bar.
Motherwell manager had to change it and, at the interval, he replaced the ineffective Liam Grimshaw and Andy Rose with Craig Tanner and Gael Bigirimana respectively in an attempt to inject some vitality into his charges.
It seemed to have worked when Cedric Kipre headed home from Tanner’s free-kick seven minutes after the restart but, although referee Don Robertson awarded the goal, following protests from goalkeeper Tomas Cerny and a consultation with assistant referee Gary Hilland, he reversed his decision.
Lessons were not learned, however, and Bowman reduced the leeway two minutes later with a header from a Frear corner. Cerny only just failed to keep that out but he did manage to push behind a netbound effort from the striker shortly afterwards as Motherwell ramped up the pressure.
Bowman was cautioned for going in with his elbow on Niall Keown (no, really), one of the few poor challenges in a hard-fought contest.
Thistle have the highest goals-against column in the top tier and that was underlined when Tanner was allowed to slalom through their rearguard before drilling the ball beyond Cerny’s outstretched left hand.
Frear could have equalised in stoppage time but his point-blank header from Richard Tait’s cross was directed straight at Cerny.
Motherwell could have gone above Hearts into fifth with a draw here but they now have only one win from their last eight matches. And they face a potentially treacherous trip to Rugby Park to take on in-form Kilmarnock on Saturday.