Former Rangers and Scotland striker Steven Thompson on Radio Scotland: "You can prepare as much as you like, and no doubt Mark Warburton will have done fastidiously before this game.  But it is individual mistakes that are costing Rangers.  First goal - a set-piece. Second goal - mistake by Kiernan. Then an experienced player in Senderos getting himself sent off."  

Moussa Dembele goes so close to a hat-trick with his shot but Wes Foderingham palms the ball round the post. 

BBC Radio Scotland commentator John Barnes informs listeners that the last time a Celtic player scored a hat-trick in a league game against Rangers was Stevie Chalmers in 1966, in a 5-1 victory.

Rangers assistant manager Davie Weir is sent to the stand...or is the former Ibrox centre-half going to the changing room to find his boots?

What on earth was the big Swiss defender thinking of? Already on a booking, he mis-timed his jump and threw up an arm to punch the ball away. Rangers now have only two recognised defenders on the pitch - full-backs Lee Wallace and James Tavernier. Incredible.

Philippe Senderos is sent off for deliberate hand ball.

Celtic midfielder Stuart Armstrong hammers in a shot but Wes Foderingham dives to his right to prevent a fourth goal for Celtic. Meanwhile, Scott Brown is coming off to be replaced by Callum McGregor.

Winger Harry Forrester comes on for injured Rangers centre-half Rob Kiernan - he limps up the tunnel. Mark Warburton has chosen Forrester ahead of a straight replacement in Clint Hill. It's a bold move.

Rob Kiernan is booked for a foul on Moussa Dembele...and it looks like the Rangers centre-half has injured his ankle.

The Celtic fans are enjoying this, doing the "Poznan", but just how should Rangers manager Mark Warburton deal with being two goals down with 25 minutes to play?

Former Rangers and Scotland striker Steven Thompson on Radio Scotland, just before the Waghorn for Miller substitution: "Dembele did awfully well for the goal but Rangers' defending was not smart again.  They probably have to make changes now, whether it is tactically or personnel-wise.  At 3-1 down, it is going to be a very big ask."

For Rangers, Martyn Waghorn is on for Kenny Miller, and for the hosts Patrick Roberts replaces James Forrest.

Ouch!published at 57mins

57mins

Celtic 2-1 Rangers

Rangers scorer Joe Garner and Celtic midfielder Nir Bitton receive treatment after clashing in the middle of the pitch. They were both in the air when they made contact. Willie Collum, sensibly, orders a drop ball which is contested by Joey Barton and Scott Brown - the Scot comes out on top.

Pat Bonner
BBC Scotland pundit

"Rangers have started this half quite well.  They are getting a lot more possession.  Andy Halliday has brought fresh legs and running and energy to get into good areas.  It has been a bright start for them."

Sub Stuart Armstrong is involved straight away as he passes to James Forrest, who smacks a left-foot shot at the Rangers goal where Wes Foderingham makes a comfortable save.

Stuart Armstrong is on for Celtic midfielder Tom Rogic.

With Rangers looking lively, perhaps thanks to Andy Halliday in the middle of the park, they create a chance as Barrie McKay curls a right-foot shot that misses Dorus de Vries's left-hand post by a few inches.

No player has scored a hat-trick in an Old Firm match since Ally McCoist in the 1983/84 League Cup Final, which Rangers won 3-2 after extra time.