St Mirren 1
Mehmet 70(pen)
St Johnstone 3
Quinn 13 Jackson 20 Macdonald 28
St Mirren 1 St Johnstone 3 March 18 2008
St Mirren were swept aside in emphatic style at Love Street as St Johnstone won 3-1 to cruise into the last four of the Scottish Cup.
Rocco Quinn, Andy Jackson and Peter MacDonald all helped themselves to a goal apiece in Tuesday night's quarter-final replay to secure a comfortable win for the First Division side.
Even an unsuccessful penalty from Paul Sheerin - and a successful one from Billy Mehmet - could not take the gloss off a victory which sets up a meeting with Rangers or Partick Thistle in the next round.
Quinn opened the scoring with a 14th-minute volley from a Liam Craig cross, Jackson rifled in six minutes later after MacDonald's dummy and the latter curled in the third on 28 minutes from the edge of the box.
St Johnstone face the winners of Wednesday night's Rangers v Partick tie in the semi-finals on Sunday April 13.