The Light Blues crashed out of the first round of the competition after extra time at Station Park yesterday, against the backdrop of a boardroom battle that sees a group of shareholders attempt to remove key figures from the board.
A blistering post-match verbal attack on Charles Green - who claimed in a newspaper article yesterday that McCoist must win a cup this year - suggests the manager and the former chief executive turned club consultant are also on a collision course.
However, McCoist's assessment of the match itself was much calmer as he pointed out that, with a transfer embargo restricting the use of their new recruits, the team who slumped to defeat was effectively the same group of players who struggled at times in the bottom tier of Scottish football last term.
He said: "It is disappointing but, at the same time, we had a lot of disappointing results last year with the same team so I don't think we should be getting carried away.
"It's obviously a big disappointment, we're not kidding ourselves on, but I would fully expect, come September, to be a lot stronger in all areas.
"It's going to be a tough month for us, we've just got to get through this month, and then we will be far stronger."
The signing ban means Rangers must wait until September 1 to register their eight new players.
Nicky Law and Jon Daly were both able to feature as trialists in last week's 4-0 win over Albion Rovers in the Ramsdens Cup.
But competition rules prevent the use of any trialists from participating in the League Cup, meaning all new recruits were restricted to watching from the stand yesterday.
McCoist added: "I'm very, very disappointed but I'm realistic.
"We had eight players who will play for us sitting in the stand. We should remember that.
"The eight players will certainly come in and help out some of those younger boys who played. I'm full of confidence that we will make the next stage in the league."
Fellow Scottish League 1 side Forfar took an early lead through Gavin Swankie before Fraser Aird forced the tie into extra time with a late leveller.
But Rangers' hopes of progression in the competition were shattered when Swankie struck again deep into extra time.
McCoist said: "I'm disappointed to lose a cup tie to be quite honest.
"It was a game where I felt, in the first half, that the conditions played a big part in the game.
"When we got the equaliser we should have gone on to win it, we certainly had chance to go on and win it.
"But we were vulnerable to longer balls into the box and it was a good delivery into the box. I always felt that the third goal was going to be the match-winner."
Swankie revealed how Forfar took inspiration from some of Rangers' less impressive results last season.
He said: "Playing against Rangers is where you want to be and it's brilliant for the club to win.
"I've played Rangers a few times now and I think I've only been on the winning team once. So it's massive, especially for the club.
"When you look at their results last season, there were teams who were beating them.
"So we gave ourselves a chance before the game and to beat them was brilliant.
"I thought the best we played was actually in extra time. You would have thought Rangers would have been the stronger team in extra time, but we dug in."