Kenny Miller inspired the victory when his cross was put into the Aberdeen net by Ricky Foster and then headed a great goal from a Novo cross.
However, Madjid Bougherra was sent off and will miss next Sunday’s final game of the season at Tannadice – unless Rangers mount a successful appeal.
It was one of two controversial red cards in a fraught match for the 50,295 fans.
The first controversy arose in 17 minutes. Lafferty went in hard on Charlie Mulgrew on the touchline and the Aberdeen player did not like it.
He stupidly put his face into Lafferty’s face and the Rangers player went down. There did not seem a lot of contact but the intention was there and Mulgrew was sent off.
Assistant referee Graham Chambers helped Stuart Dougal make the decision and it was his say-so which led to the dismissal of Madjid Bougherra six minutes before half-time.
Bougherra slid in with his right boot raised trying to get on the end of a Steve Davis cross and he caught Dons keeper Jamie Langfield on the head.
It was a legitimate attempt to play the ball and it was completely accidental. Incredibly, Chambers called over Dougal and he flashed a red card. It seemed incredible that in a match of such importance, Chambers would make such a call.
For the second game running an assistant referee had given a huge call against Rangers. No wonder the fans were going ballistic.
That said, for the period that Rangers did face 10 men they did not really hurt Aberdeen.
Steve Davis had a shot in 32 minutes which hit Sasa Papac and then caught the base of Langfield’s right hand post.
Then a minute later Langfield had to make a smart block from Papac’s close range shot after Mo Edu had played him in.
That must have been the disappointing aspect for Walter Smith but, like last Wednesday, he got a reaction in the second half. There was more purpose about Rangers and better tempo.
Lafferty had a shot deflected wide by Vidal for a corner and then Miller hammered a right foot shot which Langfield could not hold but Boyd could not reach the rebound.
In 61 minutes Smith made a double switch bringing back Barry Ferguson for the first time since March 21 as a replacement for Mendes and sending on Novo for Boyd.
Within six minutes Rangers had scored twice and it was Kenny Miller who was responsible for both of them.
In 65 minutes he raced down the left and then whipped over a low cross which Ricky Foster diverted into his own net.
Then two minutes later he scored a superb header from Novo’s corner making contact at the near post to give Langfield no chance.
The fans smelled blood and Novo had a chance in 69 minutes but he tried an ambitious overhead kick instead of laying the ball back and Langfield saved.
Aberdeen, though, served notice in 73 minutes that they were not out of it when Gary McDonald found space in the left channel and hit a left foot shot which skimmed the top of the bar.
Then in 77 minutes they did score. McDonald played the ball into the box from the left to find substitute Michael Paton who had time to swivel onto his left foot and beat Alexander from 10 yards.
Still the drama was not over. Novo had a chance for a third in 84 minutes when Papac found him into the box but he volleyed well wide from only 12 yards.
In the end the win was achieved and that was the main thing and it’s all about what happens next weekend.