Probably not. Recent history seems to suggest that a victory over United is the exception rather than the rule, as we've only managed it twice out of the last nine attempts. On the plus side, both of those wins came at Tannadice - and both came when Barry Robson wasn't playing, which will of course be the case tomorrow night as well.
Sunday's exertions may well take their toll on some members of the Saints squad. Gary Mason hadn't played for a few weeks and may not be deemed fit enough to have a foul given against him after being tripped up for the second time in the space of a few days. The sheer effort Saints put in against Celtic on Sunday could have an effect on fitness levels, with a few players being brought in to offer fresh legs. Chances are Mark Corcoran could start in place of Craig Dargo, while Garry Brady or Stephen McGinn could replace Mason. Stephen O'Donnell is still out, while Richard Brittain played in Monday's reserve game before it was abandoned, as did Chris Smith.
United have had an extra day off as they played on Saturday, somehow failing to score against Falkirk despite dominating the game. They have struggled a bit since Robson left - although they have only lost once - and could end up blowing a chance of European football if they don't pick up their form soon. Mark de Vries is still looking for his first Arabs goal and will cause problems as always, while Noel Hunt has scored a shedload of goals this season.
United are struggling a bit lately and we always seem to help out teams in that situation, while they'll also be out for revenge after the cup defeat. As a result, I think they'll win by a couple.