Motherwell failed to build on their opening day victory over St Mirren as they were floored by a wonder strike at Tannadice.
With the game looking to be heading for a stalemate, eight minutes from time Dundee United super sub Mario Bilate lashed the ball into the top corner to give the home side all three points.
Have lost 14 goals to United last season Stuart McCall elected for a more cautious approach with Jack Leitch replacing Lionel Ainsworth from the side who beat St Mirren.
However, they did manage to threaten after only three minutes when Josh Law let fly from 20 yards following a short corner and the ball hit the bar.
Nadir Ciftci was one of ’Well’s main tormentors last season and looked as likely as anyone on the pitch to break the deadlock.
He came close as he twisted and turned in the box twisted before unleashing a goalbound shot that was only kept out by a brave block from Stephen McManus.
But it would be Bilate, who came on for Keith Watson, who ultimately helped ignite his side.
Picking the ball up from Gary Mackay-Steven, BILATE’S first touch was poor, but his second was a cracker as he beat Dan Twardzik.
The visitors almost equalised in time added on, but Craig Reid’s shot from inside the area was deflected just wide.
Dundee United: Cierzniak, Watson (Bilate 65), Townsend, Rankin, Fojut, Morris, Dow, Paton, Ciftci (Telfer 86), Armstrong, Mackay-Steven (Erskine 86). Subs not used: Graham, McCallum, Smith, Spittal.
Motherwell: Twardzik, Reid, Francis-Angol (Ferguson 45), Carswell, Kerr, McManus, Leitch (Ainsworth 86), Lasley, Sutton (McHugh 85), Erwin, Law. Subs not used: Lawson, Nielsen, Neill, Cadden.
Referee: Kevin Clancy.