The hosts secured all three points in the City of Discovery with a comprehensive 4-2 victory to complete a disappointing week for the women of Steel.
First-half strikes from Robyn Smith & Jade McLaren had United firmly in the ascendency at the break.
Carla Boyce restored some optimism with an accurate finish moments after the restart, but a quickfire response from Danni McGinley & Neve Guthrie looked to have put the game beyond the visitors.
Boyce netted her second and a late consolation for Motherwell in the dying stages, as they bowed out with a defeat.
Manager, Paul Brownlie made two changes from the side that conceded their first Lanarkshire Derby of the season midweek.
Lauren Doran-Barr and Louisa Boyes both had to settle for a place on the bench, as Gill Inglis and Katie Rice both returned to the starting XI.
With all to play for in their current fight for survival, United wasted no time in their pursuit for safety.
With only two-minutes on the clock, a hopeful long ball caught the Motherwell defence off-guard, and Smith raced through before calmly placing her effort high into the roof of the net.
Motherwell’s woes continued moments later. Gill Inglis drilled cross from the right looked to have blatantly struck the hand of Rebecca Foote in the box, but the referee waived play on, much to the bemusement of the Motherwell technical area.
With minutes left in the opening-45, United doubled their advantage. McGinley’s looping delivery sailed towards the back post, where the lurking McLaren poked home from a yard out.
As the second half resumed, Motherwell toiled for a route back into the game.
An exceptional solo Kayla Jardine run gave her the time and space to whip a dangerous delivery across the six-yard box, and Boyce was on hand to power home a precise header.
However, less than a minute later, United restored their advantage with Motherwell the architects of their own downfall.
A mix-up at the back allowed McGinley to race through on goal, before coolly placing her strike under Emily Mutch.
The Motherwell shot-stopper was soon forced off after a collision in the box, with substitute Katie Andrews playing the remainder of the second half.
With 15-minutes left to play, the hosts looked to have put the game beyond any doubt.
Footes’s unpredictable long-ball was latched onto by Guthrie, who chipped a simple effort over the goalkeeper to put her side firmly in control.
In the dying stages of the game, Motherwell were denied their second penalty call of the game.
Gill Inglis’ low cross was brought down well by Burchill, who appeared to have been hauled down under a late challenge, but the referee again waived play on.
Motherwell would find a late consolation, as Boyce punished a defensive error to net her second of the evening, but the damage in the first half was too much to overcome and they were consigned to defeat.
Paul Brownlie’s side will face a short turn-around before facing Glasgow Women midweek ahead of a tough test against Spartans at the weekend.