Chris Kane gets toe on Glenn Middleton cross to guide St Johnstone into lead; Middleton rifles in free-kick two minutes later; Conor McCarthy bullets home response
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League Cup winners St Johnstone lifted the Scottish Cup in 2014
Hibernian already through to final on 22 May after beating Dundee United on Saturday
St Mirren 0-2 St Johnstone
Eamonn Brophy is on as St Mirren chuck the kitchen sink at this. Another great opportunity for Collin Quaner close in but he sends his header off target.
The Paisley side have spurned some very tasty chances today.
St Mirren 0-2 St Johnstone
Jake Doyle-Hayes goes into Willie Collum's little black book, just as his captain Joe Shaugnessy did for the foul that led to the second goal.
St Mirren 0-2 St Johnstone
How on earth is it not 3-0?!
A deflected cross from Glenn Middleton is met by a thumping header from Shane Rooney just six yards out but Jak Alnwick throws up a hand and somehow scoops the ball over the top.
St Mirren 0-2 St Johnstone
Allan Preston
BBC Scotland summariser on Sportsound
Quote MessageIt's 27 yards out, the goalkeeper is rooted to the spot, absolutely no chance.
Glenn Middleton
That is a cracker! Glenn Middleton lines up a free kick on the right and curls it beyond Jak Alnwick with real venom.
It wasn't in the corner but the St Mirren keeper was completely flummoxed. He hardly moved.
The Saints sub has set one up and hammered in a beauty.
St Mirren 0-1 St Johnstone
James McFadden
Former Scotland forward on BBC Radio Scotland
Quote MessageIt's a brilliant goal. Callum Booth has been brilliant in this half and it's a brilliant cross from him. It's no less than St Johnstone deserve.
Chris Kane
A lovely, flowing move from St Johnstone ends with Callum Booth feeding Glenn Middleton to cross in from the left and in comes Chris Kane to slide home his eighth goal of the season.
St Mirren 0-0 St Johnstone
Dylan Connolly on for Richard Tait as St Mirren make their second change. The Irish sub is rapid and might be licking his lips at the wide open spaces on the Hampden pitch.
St Mirren 0-0 St Johnstone
St Johnstone on the attack again and Chris Kane sends a shot on the turn over the top.
The Perth side make their first substitution, with Glenn Middleton on for Guy Melamed.
St Mirren 0-0 St Johnstone
Chris Iwelumo
Former Scotland striker on BBC One Scotland
Quote MessageFantastic ball from Durmus and Quaner will be disappointed, he almost makes too much contact with it.
St Mirren 0-0 St Johnstone
James McFadden
Former Scotland forward on BBC Radio Scotland
Quote MessageIt's a hell of a chance for St Mirren. To try and defend him, does Jamie McCart do enough to put him off? But he has to put it goalbound. It looked like a clearance.
St Mirren 0-0 St Johnstone
Another big chance for St Mirren. A colossal chance gone up in smoke!
Ilkay Durmus whips in a peach of a cross and a stretching Collin Quaner gets to it inside the six yard box but he can only steer the ball wide.
St Mirren 0-0 St Johnstone
St Johnstone midfielder David Wotherspoon takes aim from long range and his curling effort whizzes just wide of the far post.
St Mirren 0-0 St Johnstone
A change up top for St Mirren as Collin Quaner takes over from Kristian Dennis.
St Mirren 0-0 St Johnstone
The first booking of the day goes to David Wotherspoon for a late lunge.
St Mirren 0-0 St Johnstone
Shaun Rooney gets his legs in a tangle and Ilkay Durmus is suddenly in behind the St Johnstone defence. The angle is tight but the shot is fierce and Zander Clark needs to push it away.
St Mirren 0-0 St Johnstone
More pressure from the Perth Saints and the ball falls to David Wotherspoon inside the penalty area. He has a sight of goal but wants to cut back on to his right foot and his effort is blocked.
St Mirren 0-0 St Johnstone
St Johnstone are pressing St Mirren back at the moment but the Paisley side are defending their box with real determination.
St Mirren 0-0 St Johnstone
Here we go for the second half.
HT: St Mirren 0-0 St Johnstone
St Mirren chief executive Tony Fitzpatrick has time for a quick word with the Sportscene team and says there hasn't been much to separate the sides but is hoping for more from Jim Goodwin's men in the second half.
"Typical semi-final, both teams are nervous," he says.
"I'd like to see us play a bit more football but I don't think there's been a lot between the teams."