A packed Ibrox Stadium saw James Tavernier’s first half penalty and second-half headers from Antonio Colak and Mallik Tillman set up a double-header with PSV Eindhoven with a place in the continent's premier competition group stage at stake.
Former Rangers striker and manager McCoist praised the crucial goalscorer – but also the removal of the away goals rule which has altered the balance of two-legged ties in the past two years.
“There were a few interesting individual performances I thought were impressive. Tom Lawrence, particularly in the second half was excellent.
“I thought Malik Tillman looked very good although he came in and out of the game but there’s certainly a player in there,” McCoist said on talkSPORT’s radio breakfast show.
The 59-year-old did have confidence in his old side though, despite a lacklustre first leg which he had branded “very concerning” last week.
Raving about the performance he went on: “Unbelievable. I never doubted them. They got a goal at the perfect time and then were quite comfortable really, two good goals in the second half.
“What a statistic, that it’s the first time Rangers have ever come back from a 2-0 deficit. That was amazing. That’s the stat. I cannot believe that. I didn’t know that we’ve never come back from a 2-0 in Europe.
“It was incredible, the atmosphere. Brilliant.
"I also think the removal of the away goal helps as well, because it means you can be a bit more care free. Terrific.”
In a sense Rangers defied the odds in overturning the statistic that so surprised McCoist, but doing so himself gave the former Ibrox boss more reasons to be cheerful – admitting he backed captain Tavernier to score first and saw his bet come in at 8/1.
He added: "I mentioned it yesterday and got quoted 13/2. But I managed to do a bit better than that.
"I got Tavernier at 8s for first goalscorer, so this is quite a happy Scotsman here!"