ST MIRREN’S woes continue. Anchored to the foot of the Premiership, they found no respite here in the Scottish Cup, tumbling out at home to Dundee United.

The Paisley side had come from two goals down to beat Championship opposition in the last round but, a late rally aside, never really looked like repeating the trick here. United faded in the second half – and weren’t helped by Calum Butcher’s red card – but were ultimately deserving of their place in the quarter-finals.

Goals from Pavol Safronko and Nicky Clark embroidered an impressive first-half performance making Duckens Nazon’s deflected shot a mere consolation for St Mirren.

United manager Robbie Neilson was pleased with his side’s performance but was annoyed that Willie Collum didn’t send off St Mirren captain Paul McGinn for an elbow on Cammy Smith.

“The referee's decision not to send off McGinn made it a fight and a battle,” said Neilson. “Everyone starts kicking each other and he tried to calm it down by sending one of my players off.

“I don't really want to come and speak about referees because we are trying to calm it down but it went from a really good performance to a physical game where it is just kicking each other. I thought it was a disgrace. He saw it, and the fourth official saw it.”

United’s first goal arrived after 15 minutes. They were already starting to turn the screw by that point against a St Mirren side utterly bereft of confidence on the back of six successive league defeats, and the goal merely underlined that superiority.

Television pictures may show that Peter Pawlett’s shot was heading in anyway but Safranko wasn’t going to take the chance, the Slovak thrusting out a leg to redirect the ball beyond Vaclav Hladky in the St Mirren goal. Hladky, in fact, had made a terrific double stop just moments before the goal and would have been well within his rights to stare witheringly at his defenders for their lack of support.

It was one-way traffic after that for the rest of the half, United beating a regular path towards the St Mirren penalty box in search of the second goal that would all but ensure their place in the next round. It arrived just moments before half-time with the home side again not covering themselves in glory.

Jamie Robson’s ball down the left channel ought to have been comfortably mopped up by Mihai Popescu. The Romanian dallied for too long, however, creating an opening for Clark who executed the deftest of flicks over the head of Hladky to double United’s lead.

Kearney made two half substitutions to try to belatedly get his team going but it was only after Butcher had been sent off for a reckless challenge on Ryan Flynn after 62 minutes that St Mirren finally started to show some life.

Popescu struck the crossbar from McGinn’s cutback before St Mirren made the breakthrough after 77 minutes when Nazon’s shot was deflected past the goalkeeper.

That gave the home side hope but they never looked like finding an equaliser to take the tie to a replay.

“I told the players in my team talk we couldn’t do a Roy of the Rovers like in the last round,” said St Mirren manager Oran Kearney.