RANGERS’ lead at the top of the SPL is down to just one point ahead of the Old Firm game with Celtic on Wednesday after they lost 2-1 at St Mirren.
Lee McCulloch and Dorin Goian were sent off as Lee Wallace’s opener was cancelled out by Aaron Mooy before Paul McGowan’s winner on the stroke of half-time.
With the Parkhead team winning by the same score against Kilmarnock, there will be a narrow margin between the Glasgow teams when they meet in midweek.
Gers will go into that game minus the two men they lost today unless an appeal against McCulloch’s dismissal is submitted given he went for violent conduct.
But their objective will be to make up for the way things went in this one and hopes will still be high that can be achieved.
Boss McCoist made four changes to the side after being less than convinced by some aspects of his team’s play against Inverness last week.
Goian returned to the first XI after illness while McCulloch replaced Maurice Edu in midfield next to Steven Davis.
And after his winning goal against Caley Jags, Kyle Lafferty made his first start since November 29 at Kilmarnock.
Both sides began positively and after being slow out of the traps in recent weeks, there seemed to be a determination from the away team to change that.
Gregg Wylde had the first chance for Gers when he darted down the right then shot but he was off the mark and should have picked out Lafferty instead.
Moments later the Ulsterman came closer after Davis fed him but after beating Craig Samson, he pulled his effort just wide as well.
At the other end, Paul McGowan kept a frenetic start to the game going with a pot shot at Allan McGregor and after he saved, Gers charged straight upfield and scored.
Sasa Papac played a wonderful 40-yard ball down the line for Wallace and after a good first touch, he cut inside his man and beat the keeper with a low finish.
There was certainly a ‘blood and thunder’ feel to the opening phase and emotions were highly charged when Graham Carey was rightly booked for a late challenge on McCulloch.
But when the two came together again as Wylde swung a free kick in, the former Wigan midfielder appeared to elbow his opponent right in front of referee Steven McLean.
The referee was quick with his decision as he flashed a straight red card at McCulloch and moments later Wylde came off for Edu as Gers reshuffled their pack.
For a spell, the pace of the game dropped as the away team closed ranks and made it difficult for Saints to take advantage of the extra man they had.
Nevertheless, it took a sensational stop from McGregor to keep out a flicked effort by Steven Thompson from a driven corner.
And as the hosts kept probing away, they got a leveller their continued pressure deserved just before the break when Mooy drove just inside the near post a minute before the break.
Seconds before the whistle, the game was then turned on its head as Nikica Jelavic lost possession and McGowan took advantage to net.
McCoist responded by throwing on Sone Aluko for Lafferty after the restart and the Nigerian almost made an instant impact when he shot but hit the side netting.
Whittaker also had a go after some great work by Wallace but he leant back too much and drilled well over.
And with a fantastic chance when he had been slipped in by Davis, Jelavic somehow slotted into the advertising board rather than between the posts.
Rangers had really raised their game and Aluko was next to charge forward, jinking into the box and away from one man before his shot ran across the face of goal and away.
But for all the chances the champions were carving out, they weren’t getting the breaks they craved and as time started running down, their hopes of equalising faded a touch.
Frustration was kicking in and the home fans could sense victory in the air as the score remained at 2-1.
And as Goian was the next to be dismissed for pulling back Kenny McLean and collecting a second booking, their fate was all but sealed.
Tempers were fraying and Jelavic nearly came to blows with Marc McAusland before McGowan was denied a second on the line by Sasa Papac.
All of that suited Saints and as the final whistle finally brought a pulsating fixture to an end, the title race had been blown wide open.