Dundee United boss Ray McKinnon is guarding his players against complacency when they face St Mirren in the Challenge Cup final because he knows only too well the dangers of underestimating 'lower' opposition.

McKinnon was part of the United team beaten on penalties by second division side Stenhousemuir in the 1995 final of the competition and he's keen to let his squad know that the Championship's basement side will be no pushovers in Saturday's final.

"The memory of losing a cup final is not a nice feeling and that's something I want to pass on to the players," he said.

"It's important when they go out there they make sure they come off that park having given everything but with the cup in our hands.

"It's going to be massive if we win it, when was the last time a Scottish club won a cup that had teams from three different countries in it?

"Rangers celebrated last year like they won the UEFA Cup so it's important and I don't know why people are dismissing it because you enter the competition to win it."

Scott Fraser and Blair Spittal are both unavailable through injury, while Sean Dillon is expected to miss the final with an ankle knock that limited his involvement to taking kick off in his own testimonial match against Hearts in midweek.

The Tannadice club have suffered a dip in form since the turn of the year that has seen them slip to fourth in the Championship table behind Falkirk and Morton, however McKinnon believes that a win could put the spark back in his side's promotion charge.

"It's unfortunate we've come into this on the back of three defeats in the league," he added, "But it's been our own downfall why that's happened, there's been nobody who has outplayed us."

"We had a good chat this week to eradicate those individual decision making errors and if we can get the ball down and get back playing and be positive we have every chance of winning this game on Saturday.

"If you win a cup final it's going to breed confidence going into your next game and that's exactly what we'll take from it but first we want to win the game."