FT: Celtic 5-1 St Mirren - Daizen Maeda steers in early on; Reo Hatate slots home from spot with Ben Taylor dismissed for the handball; Oh Hyeon-gyu nets first Celtic strike
Mark O'Hara scores from the spot for visitors Greg Kiltie is brought down only for Matt O'Riley & Hatate to counter
AET: Ayr 4-1 Elgin - Kane Hester puts underdogs ahead before Fraser Bryden levels at the death; Ben Dempsey & Dipo Akinyemi (2) score in ET
FT: Dundee Utd 0-1 Kilmarnock - Kyle Vassell nods in from Danny Armstrong corner; Loick Ayina sent off late on for hosts on debut
FT: Livingston 0-3 Inverness CT - Billy McKay gives Championship club advantage before Sean Welsh makes it two; McKay nets third
FT: Raith Rovers 3-1 Motherwell - Jamie Gullan & Sam Stanton score; Kevin van Veen lashes in scrappy effort before Ismael Goncalves scores on debut
Livingston 0-3 Inverness CT
When Livingston look like getting what would now be a consolation, Mark Ridgers produces a fine save to deny a powerful Ayo Obileye header from a corner.
They're getting nothing from this match.
Dundee Utd 0-1 Kilmarnock
Dundee United's task has been made all the more difficult by a second yellow card for defender Loick Ayina on his debut.
Billy Mckay
The pick of the bunch!
Inverness nick the ball from the Livingston defenders and Mckay produces a fine strike from the edge of the box to pick out the top corner. Super Caley go ballistic, etc etc.
Image source, BBC SportDundee Utd 0-1 Kilmarnock
Charlie Mulgrew joins the attack as United win a corner but when the ball comes to the veteran defender on the 18-yard line he balloons his shot over the crossbar. He claims there was a deflection but referee Alan Muir is having none of it.
Dundee United 0-1 Kilmarnock (70 mins)
Tyrone Smith
BBC Scotland
Just 4,973 fans at Tannadice today - those of the United persuasion are seeing their side pile it on now in search of an equaliser.
Livingston 0-2 Inverness CT
Well, well, well. We all love a good Scottish Cup tale and this could be some tale - Inverness given a Scottish Cup reprieve and now 2-0 up. Their fans are loving it and making themselves heard.
The home are fairly quiet, apart from the odd shout of annoyance at one of their players or the referee. In fairness, Livi are trying to get back into this one but so far it's not working.
Image source, SNSBilly Mckay put Inverness in front
Dundee Utd 0-1 Kilmarnock
Kyle Vassell headed Kilmarnock in front at Tannadice - his first goal for the club.
Image source, SNS
Image source, SNSRaith Rovers 2-1 Motherwell
Raith are living dangerously!
A nick off a defender's knee bounces off the top corner of the post, nearly dipping in.
Connor Shields
Connor Shields pulls a goal back for Queen's Park in the Scottish Championship.
Image source, BBC SportSean Welsh
The upset is definitely on!
It looked like the chance had gone, when Daniel Mackay's poor first touch drew him away from goal. But he was able to keep the ball alive and when the ball was clipped in, Sean Welsh clipped his header in off the post.
Image source, BBC SportCeltic v St Mirren (17:30)
Celtic: Hart, Johnston, Carter-Vickers, Starfelt, Taylor, McGregor, Turnbull, Mooy, Jota, Maeda, Kyogo.
Substitutes: Bain, Haksabanovic, Abada, Kobayashi, Oh, Iwata, O'Riley, Hatate, Forrest.
St Mirren: Carson, Fraser, Gallagher, Taylor, Strain, Baccus, O'Hara, Gogic, Tanser, Greive, Main.
Substitutes: Urminsky, Shaughnessy, Kenny, Small, Flynn, Kiltie, Offord, Jamieson, Watt.
Livingston 0-1 Inverness CT
Livingston are piling the pressure on as they try to find an equaliser and ensure they're not on the end of another cup upset this afternoon.
Kurtis Guthrie, on as a half-time sub, is the latest to go close, glancing a header wide.
Dundee Utd 0-1 Kilmarnock
Tyrone Smith
BBC Scotland
That goal is a real sucker punch for United, who had started the second half really strongly. Hopefully, we now have a real game on our hands at Tannadice.
Image source, SNSRaith Rovers 2-1 Motherwell
Brian McLauchlin
BBC Sport Scotland at Stark's Park
And all of a sudden we have a real cup tie non our hands! The Motherwell fans have finally found their voice and it now looks like there is a belief from the players that was missing in the opening 45 minutes.The Raith players are throwing their bodies on the line but you have to question just how long they can keep this up after a gruelling 120 minutes in midweek against Dundee.
Image source, SNSKevin van Veen's goal has given Motherwell hope
Kyle Vassell
Against the run of play, Danny Armstrong's corner from the right is headed into the net from six yards by Kyle Vassell.
Image source, BBC SportDundee Utd 0-0 Kilmarnock
United register a shot on target for the first time in the match. Mathew Cudjoe is a bag of tricks on the right wing and feeds Craig Sibbald 25 yards from goal. The United midfielder smashes a left foot shot that Sam Walker does very well to save to his left.
Liam Smith goes even closer two minutes later, drifting into the box and heading Glenn Middleton's cross off the crossbar. This is so much better by United.
Dundee Utd 0-0 Kilmarnock
Tyrone Smith
BBC Scotland at Tannadice
United have started the second half with a lot more intent and they have carried more threat in the opening minutes since the interval than they did in the entire first half.
Billy Mckay
Against the run of play, the Championship side have the lead! A long ball over the top put Billy Mckay one-on-one and the veteran striker finished high into the top corner.
Inverness weren't meant to be in the last 16 - they might be in the quarter-finals now.
Image source, BBC SportKevin van Veen
It's not the prettiest, but Well won't care!
Kevin van Veen latches on to a bouncing ball in the box and stabs it beyond Jamie MacDonald to kick Motherwell into action.
Image source, BBC SportLivingston 0-0 Inverness CT
There has been a half-time change for Livingston - Kurtis Guthrie is on up top for Steven Bradley. A slightly more attacking swap.