United's miserable home form continued as they went eight league games without a victory following a 2-0 defeat to Motherwell.
It had started so well for the Tangerines when they were given the first opportunity in the fifth minute. A long Bullock clearance presented McIntyre with a clear sight of goal, but he allowed the ball to bounce of his shoulder. The same player then rattled in a 22 yard shot three minutes later but it went narrowly wide.
Again, in the 10th minute as United increased the pressure, the striker was guilty of over elaboration when set up superbly by Scotland. This was followed by Scotland's rasping shot which flew over in the 16th minute.
Against the run of play, however, â€˜Well were awarded a soft penalty in the 21st minute.
Referee Hugh Dallas adjudged Bullock to have pulled down Adams as the ball appeared to go over the byline. The same player then easily sent the keeper the wrong way to net the opener.
As a shocked United tried to retrieve the situation, McIntyre then headed a Griffin free kick wide from an excellent position. But, despite their continuing possession, the Tangerines continued to lack the guile and creativity to break down a resolute visitors' defence.
For their part, Motherwell defended well and broke with pace too, testing the home defence.
Four minutes from the break, an Easton header at McLaren's corner looked net bound until Adams hooked the ball off the line with Marshall stranded.
To compound United's misery, on the stroke of half-time, McIntyre who had played poorly, missed a penalty having been awarded the spot-kick when Partridge had held his jersey.
In a dull second half, United's form on the day in front of goal was epitomised in the 78th minute when substitute Coyle blasted over from only four yards with the goal gaping.
And it got worse for the hosts when Adams notched his second in the final minute with a lob over the advancing keeper in the roof of the net.