Keith Lasley came in for Steven McGarry in a Motherwell side playing their first game in 10 days.
United had this week named a stand after chairman Eddie Thompson, while the match was played with ball's paying tribute to Phil O'Donnell, the Motherwell midfielder who died the last time the two sides had met.
But it was not a match fit to commemorate the two men high in the affections of their respective clubs.
Close-range efforts from De Vries and Well's Bob Malcolm failed to trouble either goalkeeper.
And Motherwell boss Mark McGhee made an early substitution by withdrawing left-back Steven Hammell and replacing him with midfielder Simon Lappin.
But it was United who had the better chances of a scrappy first half.
Noel Hunt beat Smith to a Christian Kalvenes cross, but the striker's header struck Steve Craigan's head and flew well over the bar for a corner.
Phil O'Donnell's signature adorned the match balls
Motherwell's Ross McCormack lacked composure and accuracy as he sent a snap shot from the edge of the box high into the crowd as the first half drew to a disappointing end.
United were the more dangerous as the second half began, Gary Kenneth being the one to beat Smith to a Kalvenes cross only to head wide from 10 yards.
A De Vries shot squirmed wide from the edge of the box.
Zaluska did well to clear on the edge of his box after McCormack beat United's offside trap by slipping the ball through to strike partner Chris Porter.
And a Craigen header powered just wide from a McCormack corner as Well began to become more of a threat.
But, moments after replacing O'Brien, Swanson produced the one piece of quality that deserved to win the game.
Hunt squandered a chance to make it 2-0, driving the ball wide after being set up by cleverly Swanson.
But De Vries made no mistake when he broke clear with two minutes left, rounding Smith before slotting home with the outside of his boot.
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