St Mirren finally found a route to goal against Dundee United, as a second-half Andy Dorman strike ensured the Buddies advanced to a Scottish Cup quarter-final with St Johnstone at the second time of asking.

Gus MacPherson's side would not have faced this replay at Tannadice had they taken their chances in the original encounter between the teams.

And they once again looked to be blighted by bad finishing when Craig Dargo failed to capitalise on a mistake by United goalkeeper Lukasz Zaluska.

But the forward made up for his profligacy in setting-up Dorman's 48th-minute winner, while at the other end a great performance from St Mirren goalkeeper Mark Howard was capped by an outstanding stop from Noel Hunt's late overhead kick.

The talk before this fixture may have centred on St Mirren's aggravation at the appointment of referee Alan Freeland, but in the end his role in the tie proved insignificant.

This was the first time Freeland had refereed St Mirren since a row broke out 10 months ago when he was acting as a fourth official at a game between the Paisley club and Falkirk.

St Mirren are believed to be unhappy at comments allegedly made by Freeland, prompting fears over how he would handle their matches.

However, there were no problems in the early stages against United, with St Mirren creating the first opportunity after just 10 seconds.

Mark Corcoran's low cross found Dargo, only for Christian Kalvenes to make a strong block and prevent what looked to be a certain goal.

Dargo was then inches away from connecting with another good Corcoran delivery, while strike-partner Billy Mehmet kept up the pressure on United by clipping an opportunistic effort wide.

St Mirren should have taken the lead in the 17th minute when Zaluska made a terrible error while trying to keep the ball in play.

The United goalkeeper stopped the ball on the touchline, but could not keep it in his grasp, allowing Dargo to pounce.

While the striker was faced with an acute angle there was little excuse for his subsequent miss, as an off-target shot went straight across the face of United's goal.

With Chris Smith suffering from swollen glands, St Mirren started with Howard as their keeper for the night and his first serious test was to push away a low drive from Hunt.

The Irishman continued to be United's main attacking threat, whipping a free-kick from 25 yards just wide, while the last opportunity of the opening period fell to Craig Conway, who shot straight at Howard.

The home side may have slowly improved throughout the first half, but they would continue to find the going tough against a positive and purposeful opponent.

Within three minutes of the restart, Dorman saw a shot deflect off Darren Dods and went wide, a Mehmet drive was beaten away by Zaluska, then St Mirren took the lead.

Dargo's flicked header landed straight in the path of the onrushing Dorman and the midfielder provided a composed finish.

United's response to that setback was instant with Mark de Vries knocking the ball down to Hunt, who had a shot blocked by the well-placed Howard.

An unflappable performance from the St Mirren goalkeeper was to take a turn for the worse in the 68th minute though, when he carelessly dropped a cross from Willo Flood at the feet of de Vries.

Fortunately for St Mirren the Dutchman was not able to take advantage of Howard's charity, as he shot harmlessly wide.

Two efforts from substitute Danny Swanson then lacked accuracy, while United did not have to wait long to once again be thwarted by Howard.

On this occasion the St Mirren goalkeeper acrobatically tipped over Hunt's equally spectacular overhead effort.

Corcoran should have doubled his team's advantage in injury-time, but was denied by Zaluska when clean through on goal.

It made little difference though, as St Mirren secured a last eight tie in Perth on March 8.

Teams:

Dundee Utd Zaluska, Flood, Wilkie (Dillon 82), Dods, Kalvenes (Odhiambo 88), Kerr, David Robertson (Swanson 57), Gomis, Conway, Hunt, De Vries.

Subs Not Used: McLean, Buaben.

Booked: Wilkie.

St Mirren Howard, Barron, Potter, Haining, Maxwell, van Zanten, Murray, Dorman, Corcoran, Mehmet, Dargo (Kean 82).

Subs Not Used: Mathers, Miranda, McGinn, Millen.

Booked: Mehmet, Dargo.

Goals: Dorman 48.

Att: 3,723

Ref: A Freeland (Scotland).