The Hearts defender's free-kick from 25-yards soars into the bottom corner.
But we have a VAR check with Lawrence Shankland in an offside position when the ball is struck...
BBCCopyright: BBC
GOAL Kilmarnock 4-2 St Mirren
Kyle Vassell
Oh my word. The Kilmarnock goals keep coming!
Marley Watkins' long ball over the top finds Kyle Vassell and the big striker takes one touch before rifling it into the bottom corner.
Killie changed their tactics and it's worked brilliantly.
BBCCopyright: BBC
GOAL Celtic 3-0 St Johnstone
James Forrest
Substitute James Forrest is not long on but he's already made his mark on this game.
The winger is well positioned on the right to receive Matt O'Riley's pass, take a touch and strike a left-foot shot past Dimitar Mitov.
BBCCopyright: BBC
Ouch!
Motherwell 0-1 Aberdeen
The face of Dan Casey prevents Aberdeen scoring a second.
It's a sore one for the Motherwell defender, who blocks Jamie McGrath's shot.
GOAL Kilmarnock 3-2 St Mirren
Marley Watkins
What a turnaround!
That is incredible. Danny Armstrong receives the ball on the corner of the box, dinks a nice cross in and Watkins somehow guides an inch-perfect header into the top corner.
The neck muscles to get that ball in... Unreal.
BBCCopyright: BBC
Boos for Roos
Motherwell 0-1 Aberdeen
Jane Lewis
BBC Scotland
A section of Motherwell fans are not happy with Aberdeen goalkeeper Kelle Roos taking his time with a goal kick. The boos ring out...
GREAT SAVE!
Celtic 2-0 St Johnstone
Matt O'Riley stands over a free-kick on the right, just outside the box. He fancies this one and his curving shot is touched over by St Johnstone goalkeeper Dimitar Mitov.
Post update
Motherwell 0-1 Aberdeen
Blair Spittal scuffs a shot from close range and a relieved Kelle Roos gets down to his right to smother.
If he hits that cleanly, it's surely a different outcome.
Shankland booked for simulation
Ross County 2-0 Hearts
Lawrence Shankland is absolutely furious as he's booked for diving.
The Hearts striker goes down as he attempts to spin away in the box.
Big call.
GOAL Kilmarnock 2-2 St Mirren
Danny Armstrong (pen)
The keeper went the right way, but Armstrong's penalty is too precise! It's rolled along the carpet and into the bottom corner.
He wags a wee finger at Zach Hemming - I wonder if the former Killie keeper said something in the build-up.
Either way - two goals in four minutes and Killie are level, and it's no less than they deserve.
BBCCopyright: BBC
GREAT SAVE!
Hibernian 3-0 Livingston
An incredible stop from Shamal George denies Hibs a fourth.
Emiliano Marcondes whips in a free-kick from the left, Adam Le Fondre flicks it at the near post, and it looks for all the world like it's nestling in the goal.
George leaps to his left and tips wide at full stretch. Fabulous.
PENALTY to Kilmarnock
Kilmarnock 1-2 St Mirren
Ryan Flynn fouls Marley Watkins and Killie could soon be level.
Looks like how many for Celtic...
Celtic 2-0 St Johnstone
Martin Dowden
BBC Sport Scotland at Celtic Park
That second gives Celtic the comfort to know they will likely go top again and put a little pressure on Rangers who travel to Dens Park tomorrow.
That would be heightened with a bigger scoreline. It's so tight on points and goal difference. It could prove decisive.
Expect Celtic to keep the foot down to the end here.
SNSCopyright: SNS
Nicolas Kuhn makes it 2-0 to CelticImage caption: Nicolas Kuhn makes it 2-0 to Celtic
GOAL Inverness CT 1-2 AYR UNITED
Fraser Bryden
Post update
Hibernian 3-0 Livingston
Livingston look much more threatening now, but they have a mountain to climb and so far, have yet to take the first steps of the ascent.
Tete Yengi cuts in off the left, but bends his shot over the top.
GOAL Kilmarnock 1-2 St Mirren
Kyle Vassell
That goal has been a long time coming.
It all came from a simple long ball as well. It was initially headed away, but Liam Donnelly powered a header back over the defence and at the second time of asking, Vassell poked it past the keeper.
Very much game on. It's been all Killie since that tactical tweak.
BBCCopyright: BBC
More energy from Motherwell
Motherwell 0-1 Aberdeen
Jane Lewis
BBC Scotland at Fir Park
Motherwell have made a bright start to this second half as they go in search of an equaliser. They're still having to defend at times, Aberdeen are still threatening, but the home side seem to be playing with a bit more energy.
GOAL Airdrieonians 3-2 ARBROATH
David Gold
Post update
Kilmarnock 0-2 St Mirren
Kilmarnock have changed to four at the back, with David Watson at right back, and it almost has an instant impact.
Danny Armstrong is more involved and his cross falls to Robbie Deas, who forces Zach Hemming into a fine save, with Marley Watkins unable to make the most of the rebound.
Live Reporting
Colin Moffat
All times stated are UK
GOAL AIRDRIEONIANS 4-2 Arbroath
Charlie Telfer
GOAL Ross County 2-1 Hearts
Stephen Kingsley
Vintage Stephen Kingsley.
The Hearts defender's free-kick from 25-yards soars into the bottom corner.
But we have a VAR check with Lawrence Shankland in an offside position when the ball is struck...
GOAL Kilmarnock 4-2 St Mirren
Kyle Vassell
Oh my word. The Kilmarnock goals keep coming!
Marley Watkins' long ball over the top finds Kyle Vassell and the big striker takes one touch before rifling it into the bottom corner.
Killie changed their tactics and it's worked brilliantly.
GOAL Celtic 3-0 St Johnstone
James Forrest
Substitute James Forrest is not long on but he's already made his mark on this game.
The winger is well positioned on the right to receive Matt O'Riley's pass, take a touch and strike a left-foot shot past Dimitar Mitov.
Ouch!
Motherwell 0-1 Aberdeen
The face of Dan Casey prevents Aberdeen scoring a second.
It's a sore one for the Motherwell defender, who blocks Jamie McGrath's shot.
GOAL Kilmarnock 3-2 St Mirren
Marley Watkins
What a turnaround!
That is incredible. Danny Armstrong receives the ball on the corner of the box, dinks a nice cross in and Watkins somehow guides an inch-perfect header into the top corner.
The neck muscles to get that ball in... Unreal.
Boos for Roos
Motherwell 0-1 Aberdeen
Jane Lewis
BBC Scotland
A section of Motherwell fans are not happy with Aberdeen goalkeeper Kelle Roos taking his time with a goal kick. The boos ring out...
GREAT SAVE!
Celtic 2-0 St Johnstone
Matt O'Riley stands over a free-kick on the right, just outside the box. He fancies this one and his curving shot is touched over by St Johnstone goalkeeper Dimitar Mitov.
Post update
Motherwell 0-1 Aberdeen
Blair Spittal scuffs a shot from close range and a relieved Kelle Roos gets down to his right to smother.
If he hits that cleanly, it's surely a different outcome.
Shankland booked for simulation
Ross County 2-0 Hearts
Lawrence Shankland is absolutely furious as he's booked for diving.
The Hearts striker goes down as he attempts to spin away in the box.
Big call.
GOAL Kilmarnock 2-2 St Mirren
Danny Armstrong (pen)
The keeper went the right way, but Armstrong's penalty is too precise! It's rolled along the carpet and into the bottom corner.
He wags a wee finger at Zach Hemming - I wonder if the former Killie keeper said something in the build-up.
Either way - two goals in four minutes and Killie are level, and it's no less than they deserve.
GREAT SAVE!
Hibernian 3-0 Livingston
An incredible stop from Shamal George denies Hibs a fourth.
Emiliano Marcondes whips in a free-kick from the left, Adam Le Fondre flicks it at the near post, and it looks for all the world like it's nestling in the goal.
George leaps to his left and tips wide at full stretch. Fabulous.
PENALTY to Kilmarnock
Kilmarnock 1-2 St Mirren
Ryan Flynn fouls Marley Watkins and Killie could soon be level.
Looks like how many for Celtic...
Celtic 2-0 St Johnstone
Martin Dowden
BBC Sport Scotland at Celtic Park
That second gives Celtic the comfort to know they will likely go top again and put a little pressure on Rangers who travel to Dens Park tomorrow.
That would be heightened with a bigger scoreline. It's so tight on points and goal difference. It could prove decisive.
Expect Celtic to keep the foot down to the end here.
GOAL Inverness CT 1-2 AYR UNITED
Fraser Bryden
Post update
Hibernian 3-0 Livingston
Livingston look much more threatening now, but they have a mountain to climb and so far, have yet to take the first steps of the ascent.
Tete Yengi cuts in off the left, but bends his shot over the top.
GOAL Kilmarnock 1-2 St Mirren
Kyle Vassell
That goal has been a long time coming.
It all came from a simple long ball as well. It was initially headed away, but Liam Donnelly powered a header back over the defence and at the second time of asking, Vassell poked it past the keeper.
Very much game on. It's been all Killie since that tactical tweak.
More energy from Motherwell
Motherwell 0-1 Aberdeen
Jane Lewis
BBC Scotland at Fir Park
Motherwell have made a bright start to this second half as they go in search of an equaliser. They're still having to defend at times, Aberdeen are still threatening, but the home side seem to be playing with a bit more energy.
GOAL Airdrieonians 3-2 ARBROATH
David Gold
Post update
Kilmarnock 0-2 St Mirren
Kilmarnock have changed to four at the back, with David Watson at right back, and it almost has an instant impact.
Danny Armstrong is more involved and his cross falls to Robbie Deas, who forces Zach Hemming into a fine save, with Marley Watkins unable to make the most of the rebound.