Dundee United's Paul Dixon is sent off after blocking a Leigh Griffiths shot with his hand. It's a penalty to the visitors.

Celtic burst out of the traps in the second half as James Forrest beats his man on the right and gets a cross in, but Stefan Johansen can't get a clean shot away and Radoslaw Cierzniak falls on to the ball.

Celtic get the second half under way...

Image source, SNS

Dundee United's Paul Paton was bemused, to say the least, after being sent off early on.

Alan in Eyemouth: "If Craig Thomson is supposed to be our best ref then god help us! The red cards were a yellow at best, he then sent the wrong player off & then a total dive at the penalty. Scott brown should have at least got a yellow card for his 4 fouls. Total joke."

John in Glasgow: "Talk about a bad day at the office, this is an unbelievable performance from the officials and that penalty is a clear dive in front of Craig Thomson and he sees that as a penalty......very poor indeed."

Joe on Twitter: "Ref is having an absolute mare in this one, neither were sending offs and penalty was an outrageous call COYBIG."

Well, that was some first half. Early drama and late drama, with some very ordinary stuff sandwiched in between.

There's no doubt there was a case of mistaken identity as Paul Paton was red carded early on, and Virgil van Dijk didn't appear to do much wrong either, but he was still sent packing.

Then came the late penalty and our colleagues on BBC Radio Scotland are suggesting TV pictures show that Aidan Connolly took a dive under the challenge of Anthony Stokes.

Plenty to mull over then...

Dundee United hit the front as Nadir Ciftci fires home the penalty kick. The Celtic players are furious with referee Craig Thomson, they are convinced Aidan Connolly was not touched...

Aidan Connolly goes down under the challenge of Anthony Stokes and Craig Thomson awards a penalty.

Celtic race up the other end and Stefan Johansen plays in Anthony Stokes, but his shot comes off the post. It looked like a poor effort but the pitch may well have played a part.

United's Calum Butcher takes a shot from the edge of the box, it's going wide but Ryan Dow redirects it and the ball comes back off the inside of the post.

Celtic's Stefan Johansen is a lot closer with this effort as he drives in a shot from 30 yards that almost catches Radoslaw Cierzniak out, the United keeper does make the save though.

Emilio Izaguirre knocks the ball into the box and Stefan Johansen tries an overhead kick, but the Celtic midfielder gets it all wrong and the ball falls to Sean Dillon, who clears his lines.

We're heading into the last five minutes of the first half and other than that early red card incident, there hasn't been a great deal to get excited about.

Jim in Netherlee: "You seriously wonder about officials. Paul Paton was actually nearer Dens during the incident!"

Pete: "Please can we have video refereeing?"

Stephen Hay on Twitter: "Dundee Utd need to take some of the transfer money and pay a groundsman. A disgraceful pitch for a showcase game."

Dundee United's Ryan McGowan gives up possession to Anthony Stokes and he breaks away, but his attempted pass to James Forrest is poor and the chance is gone.

Willie Miller
BBC Radio Scotland pundit at Tannadice

"It's a poor game of football and both teams are capable of much, much better. The ball is up in the air and there's no pattern to the game. We're hoping it will settle down and we'll get a game of football."

Image source, SNS

Dundee United and Celtic are both down to 10 men after Paul Paton and Virgil van Dijk were red carded early on. It's unlikely we've heard the last of this one though.

Scott Brown makes a brilliant tackle to deny Aidan Connolly a shot at goal but the Celtic skipper then commits a foul on the edge of the area. United's Nadir Ciftci tries to pass the ball into the net from the free-kick but it goes harmlessly wide.

The hosts play some nice stuff on the edge of the Celtic area and earn a corner, but Nir Bitton clears the danger.

It's all a bit scrappy at Tannadice.