Scott Sinclair scores twice from close range for Celtic after being denied from the spot
Timothy Weah marks debut with goal to make it three for holders
10-man St Mirren come from two goals down to beat Alloa
Mark McGuigan's header earns Stenhousemuir a draw at Aberdeen
Ross County hold on as Brian Graham's double edges out Motherwell
McCracken header gives Junior side Auchinleck famous win
That's all from me after a long day of Scottish Cup action - and it still isn't over this weekend.
Join us tomorrow as Hearts host Livingston in the final fourth-round tie.
It's live on BBC One Scotland, BBC Radio Scotland and here online too.
Scottish Cup fourth round
Image source, BBC Sport
FT: Celtic 3-0 Airdrieonians
On-loan PSG striker Timothy Weah tells BBC Scotland "it's really a dream come true" after scoring his debut goal for Celtic.
Now the on-loan PSG teenager wants to "get to work and get busy" and score a few more.
"It's a really good vibe," adds the United States international. "The boys have made me feel really at home and it's been easy to settle in.
"I didn't know what to expect. I just wanted to go out there and play with a clear head."
Image source, SNSFT: Celtic 3-0 Airdrieonians
Celtic manager Brendan Rodgers is delighted with his side's start to the defence of the Scottish Cup after returning from their winter break.
"It took us a bit of time to get going, but after that first 15-20 minutes, we started to find the gaps," he tells BBC Scotland.
"Scored three goals, missed a penalty, had a lot more chances and had a goal ruled out that would have given Scott a hat-trick."
Image source, SNSOliver Burke pleased Brendan Rodgers on his Celtic debut
It's been a long day in the Scottish Cup and it seems like a lifetime since Auchinleck Talbot became the first junior side to have reached the fifth round after their 1-0 win over Championship side Ayr United.
That remains the result of the day, but it is closely followed by Stenhousemuir, sitting bottom of League One, forcing a replay away to Aberdeen from the Premiership.
Dundee, bottom of the top flight, also face a replay away to Queen of the South.
Championship leaders Ross County won away to top-flight Motherwell, while League One sides East Fife and Raith Rovers beat second-tier teams.
Meanwhile, St Mirren came from behind with 10 men to ease the pressure on the side battling against relegation in the top flight by beating Alloa Athletic.
Image source, SNSFT: Celtic 3-0 Airdrieonians
Pat Bonner
Former Celtic goalkeeper on BBC Sportsound
Image source, SNSTimothy Weah scored on his Celtic debut
Quote MessageTimothy Weah looks quick and strong. He can be a real asset for Celtic. I'm not sure Oliver Burke is an out-and-out striker, but his movement was better in the second half and he'll be happy to get 90 minutes under his belt
FT: Celtic 3-0 Airdrieonians
Jim Duffy
BBC Sportsound summariser
Quote MessageCeltic are miles ahead of Airdrie in every department. But they kept at it and they had that one chance. If they had got that right on half time, you never know, but Celtic had more gears to go through
FT: Celtic 3-0 Airdrieonians
FT: Celtic 3-0 Airdrionians
Scott McDonald
Former Celtic striker on BBC Sportsound
Quote MessageIt was damage limitation in the end, but Airdrie stuck to their tasks. They can be proud of their performance. They held their own for the majority of the game. In the end, Celtic were comfortable victors
Holders Celtic ease into the fifth round of the Scottish Cup with a convincing win over a battling Airdrieonians.
It might have been different had home goalkeeper Scott Bain not made a triple save to deny the visitors an equaliser on the stroke of half-time.
But two Scott Sinclair goals and a third from Timothy Weah give Brendan Rodgers' side a comfortable passage.
Indeed, Celtic could have won by more against their League One opponents had it not been for several fine saves from David Hutton.
Image source, SNSCeltic 3-0 Airdrieonians
Image source, SNSTimothy Weah didn't take long to score on his Celtic debut
Celtic 3-0 Airdrieonians
Oliver Burke has a great chance to score on his Celtic debut.
The on-loan West Brom winger rises unmarked to meet an Emilio Izaguirre cross but makes a mess of his header from 10 yards.
That comes seconds after a low Timothy Weah cross just evades Burke in front of goal.
Timothy Weah
Timothy Weah doesn't take long to make an impact.
The on-loan 18-year-old PSG striker latches on to a fine Dedryck Boyata through ball and pokes it first time past advancing goalkeeper David Hutton.
Image source, BBC SportCeltic 2-0 Airdrieonians
Nir Bitton comes on for his first Celtic appearance in almost a year.
The Israel international has not played since picking up an injury last February but replaces captain Scott Brown in midfield.
Celtic 2-0 Airdrieonians
Visiting midfielder Grant Gallagher is booked for hauling back Callum McGregor as the midfielder broke clear towards the opposing penalty box.
Celtic 2-0 Airdrieonians
Veteran striker of many clubs Darryl Duffy is coming on for Scott Stewart.
The midfielder has had a fine match for the visitors.
Celtic 2-0 Airdrieonians
Image source, SNSScott Sinclair has scored both Celtic goals
Celtic 2-0 Airdrieonians
That's Scott Sinclair's last bit of action as he and fellow winger James Forrest are replaced.
On-loan PSG striker Timothy Weah comes on for his debut along with Mikey Johnston.
Celtic 2-0 Airdrieonians
Scott Sinclair thinks he's got a hat-trick of tap-ins on the rebound.
But the flag is up after the winger pounces following a Callum McGregor drive that comes off the foot of goalkeeper David Hutton.
The TV replay suggests it should have stood though.
Celtic 2-0 Airdrieonians
Pat Bonner
Former Celtic goalkeeper on BBC Sportsound
Quote MessageAirdrie haven't let themselves down in any way whatsoever. They've stuck to their task. We're well into the game now and they're still running, they're still going for it trying to get that goal back.