ST MIRREN booked a place in the fifth round of the William Hill Scottish Cup by easing past Second Division Brechin City on a chilly afternoon in Paisley, although they were seldom given cause to shiver.

Goals from Kenny McLean and Jon Robertson had them cruising before half-time and allowed Danny Lennon's side to coast through the rest of the tie with little cause for alarm.

Thoughts had already moved to how the Paisley side might rouse their league campaign next weekend at home to St Johnstone before this match reached a conclusion, but at least the outing allowed them to maintain the steady momentum that has been set during a week that has also brought four points in the league. There can be some contentment in that, given St Mirren were made to endure six successive defeats before last weekend's win over Dundee. That the Dens Park side remain just five points behind at the bottom of the SPL is perhaps a little less reassuring, though.

Yesterday, Lennon's men were able to enjoy the novelty of a relatively hassle-free Saturday. In last year's competition they required a replay to overcome First Division Hamilton Academical, but there was little chance of Brechin forcing that outcome.

Gary Teale saw his shot deflected on to the base of a post and one from McLean was forced wide before the midfielder followed 32 minutes of bashful football with the opening goal.

His casual creativity was a warming feature of the afternoon and McLean can claim to have set himself up, tumbling over after a challenge from Brechin's Gerry McLauchlan before sweeping a low free-kick into the right-hand corner of the net.

Craig Nelson, Brechin's veteran goalkeeper, seemed slow to get down to deal with the strike and he invited further scrutiny as St Mirren extended their lead 10 minutes later.

The match had been allowed to drift towards half-time, but Robertson offered a rude awakening when he met Teale's corner with a firm volley.

It was a fine goal to watch, yet there was a suspicion that Nelson might have played a bigger part in trying to keep it out. "It's straight from the training ground and it was meant to go back out to Teale, so he buggered that up," joked Lennon.

There were still some aspects of the performance which will require more serious attention from Lennon, most notably the ineffective display of youngster John McGinn. The teenager made only his third senior start and lasted just 32 minutes before being substituted.

His manager must now ensure that any sense of disappointment is not allowed to impede the impressive progress the young midfielder has been making. McLean was also removed later on with a groin problem, although it was not serious. "I don't know if it happened on his 199th strike or his 200th," Lennon said.

The midfielder had not been satisifed by his earlier goal and spent the rest of his time on the pitch taking pot-shots, Nelson dealing with most of them while a couple flew just over the bar.

It was an indication that the home side were confident of their route to the next round, but a lack of clear chances – Lewis Guy flicked a header on to the bar and Nelson turned a low drive from Sam Parkin past a post – was testament to Brechin's diligence.

They arrived late in Paisley after their team bus was held up and defender Jonathan Brown hobbled off after just 36 minutes, but Ray McKinnon has instilled a sense of pride within a squad that had been unbeaten since he took over in October.

"They didn't want to go back out and lose face after going 2-0 down and I thought they were excellent," the Brechin manager said.