St Mirren secured their fifth Scottish Premier League win of the season to move eight points clear of bottom-placed Dundee.
Steven Thompson's first-half double gave them a two-goal cushion going into the break.
Substitute Bob McHugh gave Motherwell hope by scoring in off the bar 15 minutes before time.
But Danny Lennon's team held on to come out on top in a pulsating match at St Mirren Park.
The game began at a frenetic pace, with both teams fizzing the ball around on a lush, greasy surface that held up well despite a recent deluge of rain.
It was the visitors, though, who looked more comfortable in possession in the opening stages.
Little surprise, then, when winger Chris Humphrey created the first opportunity to score after 10 minutes.
His piercing run into the box dazed two St Mirren defenders, but his shot at goal from 12 yards was deflected for a corner.
With the game swinging from end to end, it wasn't long before the Saints came close to scoring.
John McGinn's left-footed corner evaded everyone and dropped to the back post. Jim Goodwin slid the ball goalwards, but Keith Lasley cleared off the line.
Moments later, Motherwell were denied a lead by the woodwork. Nicky Law's drifting cross was met by Michael Higdon, whose goal-bound shot was tipped on to the post by Craig Samson.
The visitors grew in confidence from their near miss and dominated territory and possession as the interval drew near.
So it was somewhat against the run of play when St Mirren went in front - and what a lovely team goal it was.
Marc McAusland fed Jon Robertson down the right hand side and his centre found Thompson, who directed a well-placed shot from eight yards beyond Darren Randolph.
With the home fans still marvelling at the striker's festive gift, he gave them further reason to cheer just three minutes later.
Gary Teale's deep cross from the right looked like it was drifting out of play, but Thompson leapt high above his marker to nod back across goal and into the net.
St Mirren looked to stretch their lead after the half-time break.
McGinn, who was outstanding all night for Lennon's side, should have made it 3-0 when he got on the end of Lewis Guy's cut-back, but his side-foot effort was wonderfully kept out by Randolph.
Motherwell, trying to salvage something from the match, began to commit more players forward and, with 15 minutes to go, their efforts were rewarded.
Henrik Ojamaa was released down the left and his low cross was hammered into the net via the crossbar by McHugh.
By this stage, the ball hardly left St Mirren's third of the pitch, with Well relentless in their pursuit of an equaliser.
An almighty goalmouth scramble in the 81st minute seemed destined to provide a second goal for Stuart McCall's team, but some brave goalkeeping from Samson and committed blocks by the Saints backline ensured the home side's lead remained intact.
McAusland's header four minutes before time should have extended his St Mirren's lead, but for all Motherwell's late domination, St Mirren held on to provide their supporters with the perfect early Christmas present.
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