An unbelievable ten-minute first-half spell turned this game on its head as Dundee United went from dominating the match to going in for their half-time roasting three goals behind.
Not even the most optimistic Motherwell fan would had predicted what was about to transpire after the first 20 minutes.
As for the Tangerines, not only did they suffer the embarrassment of conceding four goals at home but they also slipped into fourth place in the league table after Aberdeen's fabulous result against Celtic.
After starting off in their usual confident manner, stroking the ball around, the Tangerines contrived to miss a couple of good opportunities and were made to pay heavily.
The visitors took the lead against the run of play when a fabulous cross from Jim O'Brien gave Marc Fitzpatrick the chance to plant his header into the corner of the net.
And it was almost 2-0 a couple of minutes later when Scott Robertson was forced to head a wonderful left-foot volley from David Clarkson off the line.
However, the visitors did grab their second goal in the 27th minute when Maros Kimpl's deflected shot from the edge of the penalty area flew past Lukasz Zaluska and into the back of the net.
The match was finished as a contest in the 33rd minute after some shocking defending by Gary Kenneth.
He tried to dribble the ball out of defence only to be easily dispossessed by Chris Porter who set up O'Brien to smash the ball high past Zaluska.
After the break another error by the woeful Kenneth almost gave Porter a chance to put his name on the scoresheet.
However, the Steelmen striker was handed a gift to make it 4-0 in the 63rd minute.
Substitute Danny Swanson completely miscontrolled the ball before allowing Fitzpatrick to roll a pass through for Porter to smash his 12-yard shot past Zaluska.