It is unclear whether Martin O’Neill will lead out Celtic in next month’s League Cup final. For now, the interim manager will settle for taking them there. St Mirren lie in wait after a frantic, controversial semi-final in which the 10 men of Rangers competed admirably. Celtic needed extra-time to see off their oldest foes. The outcome will matter far more to O’Neill than the earlier scale of worry Rangers caused him. A turbulent week for Celtic, which included the resignation of Brendan Rodgers, ended with their supporters hailing O’Neill in song.

Rangers’ task was rendered harder by the actions of Thelo Aasgaard seven minutes before the interval. The midfielder was high and reckless when catching Anthony Ralston, a red card the correct punishment. Rangers felt the numbers should have been levelled in first half stoppage time after the Celtic centre back Auston Trusty crazily kicked the head of Jack Butland. Trusty escaped with a booking.

Celtic were a goal to the good by that point and seemingly well on course for the final. Johnny Kenny escaped the attentions of a clutch of Rangers defenders to head home an Arne Engels corner.

Rangers’ second-half showing was strong despite the...