Scottish Cup fever may have been gripping the country over the weekend, but it’s fair to say that the only fever taking hold of the natives of Perth was down to the inclement weather.

Credit must go the ground staff at McDiarmid Park for getting this one on, but the hardy band of regulars that filed in to witness their side meekly exit the famous old competition must have wished they hadn’t bothered.

As for Kilmarnock, their travelling support would have headed south delighted to be in the fifth round for the first time in three years, and encouraged by the manner of their victory, which was comfortable in the main. Manager Gary Locke, under-fire so often this season, deserves credit for the way his well-organised side defended, and for the threat they posed on the break during the first-half in particular.

A needless foul by Dave MacKay on the excellent Greg Kiltie on the edge of the area gave the visitors the early opportunity to open the scoring, and it was one that Craig Slater was not about to pass up.

With Stevie Smith looking the likelier option to take, Slater stepped up and placed a glorious effort high past Alan Mannus into the top right-hand corner with just 6 minutes on the clock.

Josh Magennis then hit a fresh-air shot inside the area as the visitors continued to look the sharper in the early stages.

St Johnstone’s only threat in the opening half hour came from two free-kicks at a similar range to the one Slater fired home for Kilmarnock, but David Wotherspoon and then Dave MacKay floated their efforts over Jamie MacDonald’s bar.

The visitors might have extended their lead as we approached the break, but Josh Magennis’s effort at the back-post from Stevie Smith’s free-kick was beaten behind by Mannus. From the resultant corner the pair combined again, but this time the Northern Ireland striker’s volley flashed past the near post.

There was still time before the break for the home side to stake a claim for a penalty, but their appeal for a trip by Rory McKenzie on Brian Easton after the Killie midfielder had presented the ball to the left-back in the area was waved away by referee Kevin Clancy.

The home fans would have been hoping for a reaction after the interval, but again it was the visitors who started brightly with the impressive Adam Frizzell feeding Magennis again who brought a save from Mannus at the near post.

Nice play between Kiltie and McKenzie on the right then allowed the latter to float a ball into the six-yard area where Frizzell got under it slightly to nod over.

Finally, the home side threatened the visiting goal ten minutes after the restart, as Magennis’s headed clearance from an Easton corner landed at the feet of Wotherspoon on the edge of the area.

He hit his first time volley into the turf, but it bounced through to Joe Shaughnessy who helped the ball just over the bar with a glancing header from close-range.

Just after the hour they tested MacDonald when a neat one-two between Davidson and Wotherspoon gave the latter the chance to get a fierce effort away that the Kilmarnock keeper did well to get behind for a corner. He made rather a hash of Easton’s resultant delivery, punching the ball off the back of one of his own defenders, but the visitors managed to scramble the ball clear.

Tommy Wright made a double substitution to try and get back into the game with Graham Cummins and John Sutton entering the fray, and Sutton might have made an immediate impact.

Chris Millar’s cross came off the face of the bar, and when Wotherspoon drove the ball back into the area Sutton stretched to make contact but couldn’t keep his effort down.

Millar had to limp off with a hamstring injury, leaving the home side to play out the last few minutes with ten men with all substitutions made.

Quite how they didn’t equalise in the final minute though is anyone’s guess, as a driving run from Davidson allowed Sutton, MacKay and then Cummins to hammer the ball at MacDonald from close range, but the Kilmarnock stopper pulled off a series of astonishing blocks to put his side into the hat for Monday’s draw.

ST JOHNSTONE: Mannus; MacKay, Shaughnessy, Anderson, Easton; Wotherspoon, Davidson, Millar; O’Halloran (Thomson, 79’), MacLean (Sutton, 65’), Kane (Cummins, 65’).

Booked: Davidson (38’)

KILMARNOCK: MacDonald; Syme, Ashcroft, Balatoni, McHattie; McKenzie (Findlay, 82’), Kiltie (Higginbotham, 75’), Slater, Smith; Frizzell; Magennis.

Scorers: Slater (6’)

Man of the match: Jamie MacDonald (Kilmarnock)

Referee: Kevin Clancy

Attendance: 3147