Postpublished at 21:30 British Summer Time 26 September 2018
Closing stages now and there are three sides in front. As things stand, Celtic, Hearts and Rangers are joining Aberdeen in the semi-final draw to be conducted later.
Summary
Aberdeen v Rangers & Hearts v Celtic in last four
One semi-final could be played at Murrayfield
St Johnstone 0-1 Celtic; Rangers 4-0 Ayr; Hearts 4-2 Motherwell
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Postpublished at 21:30 British Summer Time 26 September 2018
Griffiths nails 'hardest chance'published at 21:29 British Summer Time 26 September 2018
St Johnstone 0-1 Celtic
Billy Dodds
Former Scotland striker on SportsoundIt was Leigh Griffiths' hardest chance. It was the one time Richard Foster switched off and was caught ball watching - Kieran Tierney gets beyond him and puts in a lovely cross.
It drops to Griffiths, it's on his weaker right foot, but he smashes it low into the net.
GOAL Hearts 3-2 Motherwellpublished at 21:28 British Summer Time 26 September 2018
Olly Lee
With just two minutes to go, Olly Lee gets to the ball inside the box and finds the left hand side.
What a finishpublished at 21:28 British Summer Time 26 September 2018
Hearts 2-2 Motherwell
Brian McLauchlin
BBC Sport Scotland at TynecastleJust when you thought Hearts were going to score a third and kill the game BANG! What a finish by Ryan Bowman.
Image source, SNSImage caption, Bowman brought Motherwell back on terms
Postpublished at 21:27 British Summer Time 26 September 2018
Hearts 2-2 Motherwell
A good chance for Hearts. Steven Naismith makes a run, cuts inside and places the ball into the path of Arnaud Djoum who should hit the target, but he screws his shot well wide.
GOAL St Johnstone 0-1 Celticpublished at 21:25 British Summer Time 26 September 2018
Leigh Griffiths
Celtic eventually get the breakthrough.
James Forrest's header from Kieran Tierney's cross is blocked by Scott Tanser but Leigh Griffiths picks up the rebound and slips the ball past Zander Clark.
'Brilliant' Bowman levels for Wellpublished at 21:23 British Summer Time 26 September 2018
Hearts 2-2 Motherwell
Allan Preston
BBC Scotland summariserIt was a brilliant goal. Long kick out from Zdenek Zlamal, a header back from Motherwell goes 30-40 yards and Ryan Bowman's on to it like a flash. Zlamal had no chance - right into the top corner.
CLOSE!published at 21:22 British Summer Time 26 September 2018
St Johnstone 0-0 Celtic
Yet more Celtic pressure ends with James Forrest's shot deflected wide of the St Johnstone goal.
GOAL Hearts 2-2 Motherwellpublished at 21:20 British Summer Time 26 September 2018
Ryan Bowman
What a goal from Ryan Bowman. The ball drops over his shoulder, and he smashes the ball from the 18 yard line, and Motherwell are back on level terms.
CLOSE!published at 21:20 British Summer Time 26 September 2018
St Johnstone 0-0 Celtic
Tom Rogic's shot comes off Celtic team-mate Mikael Lustig and the deflection diverts the ball wide.
Postpublished at 21:17 British Summer Time 26 September 2018
St Johnstone 0-0 Celtic
More frustration for Celtic as Leigh Griffiths' header flashes across the face of goal.
Tom Rogic replaces Callum McGregor for the visitors.
CLOSE!published at 21:16 British Summer Time 26 September 2018
St Johnstone 0-0 Celtic
David Wotherspoon cuts in from the right and swerves a left-foot shot wide of the Celtic goal.
GREAT SAVE!published at 21:15 British Summer Time 26 September 2018
St Johnstone 0-0 Celtic
Leigh Griffiths latches on to a loose ball and looks certain to score but his low shot is blocked by St Johnstone goalkeeper Zander Clark.
Postpublished at 21:14 British Summer Time 26 September 2018
Hearts 2-1 Motherwell
Tempers are fraying in the dugout. Manager Craig Levein and Stephen Robinson are both in amongst it. Fortunately there are no casualties and play gets back under way.
Meanwhile, Hearts' Callumn Morrison appears to have done his hamstring, but is remaining on the pitch.
Image source, SNSImage caption, Hearts players celebrate Peter Haring's goal
GOAL Rangers 4-0 Ayr Unitedpublished at 21:12 British Summer Time 26 September 2018
Glenn Middleton
Second goal of the evening for Glenn Middleton. The 18-year-old picks up possession from Andy Halliday, powers past his marker and nets number four.
CLOSE!published at 21:10 British Summer Time 26 September 2018
St Johnstone 0-0 Celtic
Lewis Morgan makes an early impact off the bench for Celtic, firing just over the St Johnstone goal.
Changes in Perthpublished at 21:08 British Summer Time 26 September 2018
St Johnstone 0-0 Celtic
Brendan Rodgers makes a change to his Celtic team. Odsonne Edouard makes way and on comes Lewis Morgan.
St Johnstone withdraw Drey Wright and introduce Danny Swanson.
'It's been coming'published at 21:06 British Summer Time 26 September 2018
Hearts 2-1 Motherwell
Allan Preston
BBC Scotland summariserIt's been coming. The pressure's been relentless in this second half, Motherwell are being hemmed deep in their own half. Haring slides in to meet the ball across the face at the back post.
GOAL Hearts 2-1 Motherwellpublished at 21:04 British Summer Time 26 September 2018
Peter Haring
The goal was coming. Peter Haring had a chance a minute ago, and this time he slides in at the back post to nudge Hearts ahead.
CLOSE!published at 21:04 British Summer Time 26 September 2018
Hearts 1-1 Motherwell
It's a great ball into the box from Callumn Morrison, and Peter Haring goes very close with a header.
Motherwell cannot get out of their own half at the moment.