Gus MacPherson has told St Mirren they will need to reproduce their best SPL performances if they are to get a result at McDiarmid Park.The Paisley side are looking to inflict St Johnstone's first home defeat for a year when they face the Irn-Bru First Division side in the Scottish Cup quarter-finals.

St Mirren deservedly knocked out Dundee United after two games in the previous round but MacPherson is sure the trip to Perth will be just as difficult.

The Buddies manager said: "They are undefeated all season at home and it goes back to March of last year.

"That gives them confidence but we went to some difficult places in the last couple of years - notably Parkhead, Ibrox, Tynecastle, Easter Road - and got good results.

"So we have to go in that frame of mind, that it's as tough a venue as those places.

"But we will look forward to it because we got a terrific result against Dundee United at Tannadice to set this one up.

"It's not going to be any easier and I think the players will understand that.

"We've been playing some decent stuff and the confidence is there.

"We are playing in a positive manner and we will try to do that at McDiarmid Park."

St Johnstone reached the last four of both cup competitions last season, beating four SPL teams, including Rangers at Ibrox.

And the Paisley Saints caused a cup shock as a First Division outfit themselves two years ago when they dumped Motherwell 3-0.

So MacPherson knows how closely matched the teams will be in a one-off game.

He added: "It's only a couple of years since we have played St Johnstone and they were really close games, and tough games. So the players will know what to expect.

"It will not be any different from an SPL game, especially away from home, because if you look at the St Johnstone squad, 80% of them have SPL experience."

St Johnstone sit third in their division after adjusting well to the loss of manager Owen Coyle to Burnley and the new stewardship of Derek McInnes.

MacPherson said of the St Johnstone boss: "He's done a quiet but efficient job. He is slowly putting his own mark on it in terms of the way they want to play, and also personnel.

"He has brought in five or six of his own player and they have got good experience - Jody Morris and Barry Wilson are household names to everybody involved in football."

St Mirren are likely to be without full-back David Barron for the game as he continues to suffer from a groin injury.

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