JACKIE McNamara wandered into the Tannadice hospitality suite in the way a contented man would leave a casino: flush with success yet slightly suspicious about the ease with which it had been achieved.

To suggest the Dundee United manager had put everything on black and won would be a slight against his squad, but there is little doubt the selection gamble he took was richly rewarded.

McNamara opted to leave Sean Dillon, Keith Watson, Stuart Armstrong and David Goodwillie out of his starting XI with an eye on Tuesday's Scottish Communities League Cup quarter- final at Inverness and next Saturday's trip to Celtic Park. He watched with some gratification as his side romped to a hugely impressive win, gilding an exhilarating exhibition of passing football with four fine goals. It could, as he said, have been more. "People would have been looking and wondering why we made all the changes, but it showed how strong the squad is," said McNamara, who was thrilled by some of the football played.

Yet for all the intricacy they showed, the goal that started the rout owed nothing to pretence. The excellent John Rankin lifted a ball over the St Mirren defence for Nadir Ciftci to chase and the forward beat Darren McGregor to nudge past debutant Marian Kello in the St Mirren goal before sliding the ball over the line. The Turk's second, eight minutes later, was equally perfunctory. After retrieving Andy Robertson's deep cross, Ciftci tumbled over Sean Kelly's leg and hauled himself to his feet to roll the subsequent penalty past Kello.

In truth, the four-goal win was the least United deserved. With Ciftci, Gary Mackay-Steven and Ryan Gauld all given licence to roam around the reference point provided by Brian Graham, the hosts continually picked holes in St Mirren's resistance, with only their profligacy preventing a more handsome scoreline. Ciftci flashed a free-kick past; Robertson lashed a shot wide; Graham twice headed over and twice came close to connecting with teasing Mackay-Steven centres; and Gauld threatened on three occasions with increasingly outrageous efforts.

Almost everything good about United's work involved the 17-year-old in one way or another. Possessed of wonderful balance, delightful touch and absurdly perceptive vision, Gauld burnished another accomplished exhibition with a fine goal after the interval. United had held possession for some time before the ball was shuttled to the teenager, who nonchalantly jinked inside before unleashing a shot high past Kello.

St Mirren's relief when Gauld was withdrawn ahead of the final quarter was understandable, but even his replacement, Chris Erskine, proved too much to handle, scoring his first United goal with a fizzing effort after a Ryan Dow pass. By then, the jig was well and truly up for Danny Lennon's side.

Kenny McLean and Paul McGowan had tried to prompt play, but the visitors were regularly reduced to sending searching balls in the direction of Steven Thompson. The Paisley team were unable to muster an attempt on goal in the opening half and their fortunes hardly improved after the interval although Thompson did head wide and should perhaps have scored after circumventing Radoslaw Cierzniak, only for the retreating Robertson to intervene. "We've no excuses," Lennon said. "The intensity and desire we've shown in the past three games wasn't there."