Higdon made an immediate impact in the 81st minute, but Motherwell goalkeeper Darren Randolph was left cursing the state of the Fir Park pitch after the striker's shot bounced off a divot and over his hand.
Motherwell missed some late chances to equalise but lacked the spark of recent performances, with Saints goalkeeper Paul Gallacher rarely troubled.
Motherwell, who had Chris Humphrey back in the team for Ross Forbes, missed the chance to move into fourth place after failing to follow up consecutive wins over Aberdeen and Hamilton.
Higdon had made way for David van Zanten after picking up a knock in a late defeat against Hibernian that exasperated manager Danny Lennon, but his players responded to his claims that they "choked" when presented with an opportunity to ease the pressure.
Motherwell had made the early running without carving out a chance and they survived a penalty claim in the 13th minute when Paul McGowan went down under Keith Lasley's rather clumsy attentions.
McGowan angrily chased referee Steve Conroy but none of his team-mates appeared to share his sense of injustice.
McGowan soon had a sight of goal with Motherwell defender Shaun Hutchinson grounded by Hugh Murray's unpunished late tackle but Randolph got down well to save the forward's near-post effort.
Lasley had a stronger claim for a foul in the area when his path was blocked by Marc McAusland after running onto John Sutton's dummy. The offence looked like obstruction but neither an indirect free-kick or penalty was forthcoming.
St Mirren finished the half in the ascendancy, showing more energy than their hosts, with Randolph holding Hutchinson's headed deflection off Murray's shot.
Randolph held two close-range headers from Craig Dargo either side of half-time and the striker soon volleyed into the side netting from just inside the box.
Lasley pulled up injured and was replaced by Stevie Hammell in the 53rd minute with Gavin Gunning moving to right-back and Tom Hateley moving into midfield.
Hateley immediately forced Paul Gallacher into his first save when the St Mirren goalkeeper parried an inswinging free-kick, and the same player then saw his powerful strike inadvertently blocked by Gunning after Sutton had held the ball up inside the box.
Jeffers also claimed unsuccessfully for a penalty when he tangled with McAusland as he tried to reach a loose ball as Motherwell pushed their visitors back.
Esteban Casagolda replaced Jeffers and Higdon came on for Dargo and the Saints substitute netted in his first real involvement.
The former Falkirk striker chested the ball down 40 yards out and brushed off Hutchinson before firing a powerful shot that took a huge kick off the uneven turf and bounced over the outstretched hand of Randolph.
Motherwell had chances to equalise but Sutton sliced well wide from 16 yards after John Potter's poor clearance.
Casagolda headed Gunning's cross over and Sutton then saw his shot brilliantly blocked by the impressive Darren McGregor.