I'll sign off now. Thanks for your company and congratulations to Celtic on reaching the last four in the Scottish Cup. Ronny Deila's men meet Inverness CT at Hampden next month, with Championship rivals Hibernian and Falkirk squaring up in the other tie.

We'll be back for more live action on Friday night when Motherwell take on Lanarkshire rivals Hamilton in the Premiership. Join us for that one, if you can.

MBEHAN: "Great victory for Celtic but the stupidity from Stokes will leave Deila unhappy #bbcscotfootball"

Paul Black: "Cruising to the treble. Ronny Deila's the man! #TrebleWinners #bbcscotfootball"

Jim Simpson: "#bbcscotfootball D.Utd just not good enough, needed to keep the two in Jan! Not gonna score in mth of Sundays!"

In League Two, Albion Rovers were 2-0 winners at Arbroath, with Gary Fisher adding to Ali Love's first-half goal.

Can anyone stop the Celtic juggernaut this season? Aberdeen can go level on points with the Premiership leaders if they win at Dens Park on Saturday lunchtime but Ronny Deila's men have played a game less and will be action against United almost as soon as that one is over.

Inverness Caley Thistle have history against Celtic in the Scottish Cup and they turned them over in the league back in August.

More from Simon Donnelly on BBC Radio Scotland

"We showed a bit of courage to keep the ball in their half at the start of the second half but then the second goal goes in and effectively kills the game. They were soft goals from our perspective."

Dundee United assistant manager Simon Donnelly

"I don't think the three games have been particularly dirty, the reaction of the Celtic players maybe influences the referee's decision (on Ryan McGowan's late red card), but I'd need to see it again."

Celtic manager Ronny Deila on BBC Radio Scotland

"It was a great performance and an important victory. We showed that we have a tempo that is very hard to cope with.

"The league is the most important thing and we want another three points on Saturday."

Image source, SNS Group

Just how many red cards will we get when these two go head-to-head again on Saturday? That's six dismissals in three games now, although two of those were later overturned. Crazy!

I'm not sure Dundee United will be looking forward to coming back to Celtic Park on Saturday. Jackie McNamara's men have now gone seven games without a win - and to make matters worse former stars Gary Mackay-Steven and Stuart Armstrong will be available to play against them.

That's three in a row for these sides, with Celtic enjoying the upper hand, winning this one and last Sunday's League Cup final after a draw at Tannadice. And guess what? They meet again on Saturday on Premiership duty.

Celtic stroll into the last four of the Scottish Cup and the treble dream for manager Ronny Deila is alive and well. Jason Denayer, Leigh Griffiths, Kris Commons and Virgil van Dijk got the goals in a one-sided affair.

Dundee United are all over the place as Celtic centre-backs Jason Denayer and Virgil van Dijk combine for the latter to knock the ball home.

We have a wee sprinkling of yellow cards as well, with Celtic pair John Guidetti and Emilio Izaguirre cautioned for their reactions to Ryan McGowan's daft lunge.

Now it's getting silly as Ryan McGowan catches Liam Henderson with a hefty challenge and the Dundee United defender will also trudge off for an early bath.

A sour end to the night for Celtic forward Anthony Stokes, who lashes out with an elbow at Paul Paton after taking umbrage at a challenge from Ryan McGowan.

We're into the last five minutes as Celtic substitute John Guidetti fires a shot over the top.

BBC Scotland's Tom English at Celtic Park

"Kris Commons gets his 12th goal of the season. The guy is a machine. Celtic must have been in some kind of trance when they thought about not giving him the deal he was looking for. One of the best Celtic signings in modern times."

A frustrating night for Nadir Ciftci takes another wrong turn as the Dundee United striker picks up a booking.

Once again, the goalscorer is withdrawn immediately as Kris Commons receives a warm round of applause and Liam Henderson gets a taste of the action.

Image source, SNS Group

Moments after missing a great chance in front of goal, Kris Commons makes amends with a classy, clipped finish from John Guidetti's pass.