As often is the case, that raft of changes has disrupted the flow of this game.

Plenty of fresh legs on but lots of tired ones too.

Derek McInnes is either telling his players to keep their heads up here or he's getting creative with a chin rest.

We're in minute 90 at Ibrox. Time's running out for his team.

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James Forrest twists and turns on the edge of the box and belts in a shot that Toby Steward palms away.

Josh Campbell and Taylor Steven have run their race for St Johnstone.

Kai Fotheringham and Danny Schmidt are the replacements.

St Mirren deal with two teasing balls into their box and they break through Alex Gogic.

What a touch that is from the Cypriot, but it all comes to an end when Jayden Richardson commits a foul.

Camilo Duran and James Forrest come on for Celtic as Haissem Hassan and Sebastian Tounekti make way.

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A dreadful ball from Cammy Devlin, put behind Kim Min-su, turns up the groans around Ibrox.

Almost a second for Celtic as Kasper Hogh finds Haissem Hassan and his delicate curling effort is palmed wide by Toby Steward.

Saints have 20 minutes to turn this around.

Kasper Hogh shoots into the Saints side netting but is offside anyway.

Rory Loy
Former St Mirren and Rangers striker on BBC Sportsound

You have to say, it looks a matter of time before St Mirren score here.

Declan John gets his shot away this time, and it's drilled narrowly wide of the far post.

It looks like the offside flag has gone up anyway.

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Celtic go to their bench and on comes Benjamin Nygren replaces Oliver Sorensen.

VAR cleared that decision, so it's still Celtic just one goal up.

Findlay Curtis just gets a toe in to prevent Declan John getting a shot away in the Rangers box.

We've hit the 80-minute mark at Ibrox.

Celtic have the ball in the net again but it will not count, for now.

Kasper Hogh had headed down Sebastian Tounekti's cross and Haissem Hassan finished.

It seems the ball went out of play before Hogh's header.

More changes from both benches as Cammy Devlin and Bojan Miovski come on for Rangers.

Nicolas Raskin and Djeidi Gassama are off.

For St Mirren, Jake Young and Eseosa Sule are on for Nikolas Agrafiotis and Ismeal Kabia.

Sam Stanton and Ruari Paton are on for St Johnstone in place of Jason Holt and Josh Fowler.

Attacking changes from Simo Valakari.

Mika Baur is found running towards the St Johnstone box but before he can get a shot away, Taylor Steven gets in and is fouled.