FraZer Wright's premonition on the morning of this William Hill Scottish Cup fifth round tie that he would score came true as St Johnstone coasted into the quarter-finals with Forfar unable to overcome the difference in class.

Wright, who hit his side's second goal, had remembered that he had scored at Station Park when he was a Stranraer player but while Tommy Wright, his manager, was pleased a possible difficulty had been overcome on the artificial playing surface, there were no post-match predictions that the Saints might go all the way to the final.

"It's pleasing to win away from home and it's important that we're in the next round," he said. "We took control of the game in the second half and I was pleased for Michael O'Halloran, knocking on the door for a first-team place, that he took his goal well.

The lack of meaningful activity in the opening 20 minutes of a Station Park exposed to the swirling Angus winds had spectators musing on a variety of issues; that there were five former St Johnstone players in the Forfar ranks and that the combined ages of Rab Douglas and Steve Banks, the respective goalkeepers was 82, surely a record the residents of the nearby old folks home would have discussed over their cocoa as they watched The Voice last night.

Martyn Fotheringham's effort from the tightest of angles had Banks worried as the ball struck the post in 22 minutes, but two minutes later the visitors grabbed the opener as Stevie May hit his 21st goal of the season, hooking Lee Croft's corner kick, headed on by Gary McDonald, too far to Douglas's left and into the net.

The goal settled Saints whose use of the ball was superior to their opponents and, using Croft's pace on the right flank, they capitalised on more Forfar hesitancy as McDonald's header from the winger's cross was palmed away in acrobatic fashion by Douglas but only as far as Wright and he ensured the goalkeeper could not stop his header.

Had Odmar Faero's thrilling 30-yard drive struck gold for Forfar rather than the crossbar just 30 seconds into the second half, the League One side would have had the lift they needed, but even when Banks dived to punch clear Mark Baxter's inswinging cross moments later, as the towering figure of Chris Templeman lurked nearby, it was difficult to see how the Loons were to find a way back into this tie.

McDonald and Patrick Cregg controlled the midfield for the Perth side while David Wotherspoon's enterprise proved problematic for the home side and when his stinging shot from the edge of the area just after an hour had been played could only be parried by Douglas into the path of O'Halloran, the Scotland under-21 international, recruited last month from Bolton Wanderers, drilled the ball home on his first start for his new club.

By then, thoughts of a potential upset were but a distant, pre-match memory and when another Saints attack was mounted with 11 minutes remaining, another Croft cross was punched clear by Douglas but simply set up another of their new boys, James Dunne, whose strike from inside the area proved too much for the goalkeeper.

After the job was completed Dick Campbell, the Forfar manager, was his usual ebullient self as he analysed the conclusive defeat of his side.

"St Johnstone impressed me today," he said. "The first goal - from May - typified that player, it was a world-class goal.

"He hadn't kicked a ball up to that point and he goes and scores a goal like that.

"That's the difference between the two teams. They were way, way in front of us. I didn't realise they were as good a side as they are."