Aberdeen's dismal winless run extended to 10 matches after their 2-0 defeat at Fir Park.
Jimmy Thelen's men have now lost their last five Premier League meetings and have picked up just three points during a run of results that has extinguished memories of their rise to the top of the table during an exciting start for the Swedish coach.
The hosts took the lead 11 minutes before half-time thanks to Euan Wilson's first professional goal, before a disastrous scoreline 60 seconds before half-time proved costly for the Dons.
Slobodan Rubisic was sent off after a clash with Tony Watt, and then straight from the start of the second half, Tawanda Masoanhase scored to double Motherwell's lead.
Aberdeen's Slobodan Rubisic has been sent off at Motherwell
The Dons' performance improved in the second half, but they were unable to get back into the game.
Both managers made four changes as they aimed to end their winless run.
Nick Walsh consulted VAR in the eighth minute after Davor Zdravkovski was penalized for a late challenge on Severt Nielsen, although a yellow card was deemed an appropriate punishment for the North Macedonia international.
The visitors' first chance of note came when Kevin Nisbet headed in from an Ante Palaversa corner kick.
Motherwell responded favorably. Masoanhase tested Ross Doohan in the Aberdeen goal with a powerful shot from the edge of the box, and then Dan Casey wasted a great chance when he headed wide after being set up by Andy Halliday.
Motherwell's Euan Wilson celebrates opening the scoring
Most of the Dons' threat was coming from set-piece situations and Aston Oxborough were forced to make a good stop when Nicky Devlin rose high to meet a Palaversa corner.
Just after the half-hour mark, a good and promising attack involving Maswanhise and Moses Ebiye ended with Watt delaying long before pulling the trigger – allowing Palaversa to come back and block the ball.
The deadlock was broken in the 34th minute. The visitors' defense opened up too easily and Watt's pass fell into the hands of Wilson, who slotted the ball into the net.
Heading into half-time, a crazy 60 seconds would leave Aberdeen with a mountain to climb.
After the encounter with Watt, Rubisic was adjudged to have head-butted the Will Man, receiving a straight red card as a result.
Things got worse for the visitors when play resumed, as a simple long ball from Liam Gordon sent Massoanhase into the net and he made no mistake as he sent an angled shot beyond Doohan.
Motherwell's Tawanda Masuinhays (right) celebrates scoring the second goal to make it 2-0
Devlin came agonizingly close to putting Aberdeen back in the game when Gordon superbly converted his effort at goal backwards.
Time was running out for the visitors, as a thunderous shot from Pallaversa hit the crossbar with 18 minutes remaining, although they had an escape after Masoanhase's shot went wide.
Stuart Kettlewell introduced Callum Slattery late on for his first appearance in over a year during the closing stages, while skipper Paul McGinn also returned from injury.
The last chance of the match went to Sam Nicholson, who was hit hard as he raced towards goal.