The Light Blues were dumped out of the League Cup the last time the two sides met at Station Park in August.
The extra-time defeat has been the only setback in what has otherwise been a 100 per cent start to the campaign.
This time, the two sides meet on league business and Scottish League One leaders Rangers are aiming to exorcise the ghosts of the cup clash.
McCoist said: "I'm looking forward to going back up there.
"It's the biggest disappointment we've had this season.
"Apart from the Forfar game, we've been fairly happy with the way things have been going.
"I've watched the Forfar game again and we did miss some chances and, on another day, we might have got a better result.
"But fair play to Forfar, they got their winner in extra-time.
"It's an opportunity for us to go back up and continue what has been a good start in the league campaign."
A transfer embargo meant Rangers were unable to field their eight new signings the last time they faced Forfar.
And, with the ban now lifted, McCoist expects his side to be far better equipped to come out on top on this occasion.
He said: "It curtailed us, it definitely weakened us, but we knew the rules before we went in to that particular competition.
"We weren't good enough on the day to get through, which was a disappointment.
"We feel we are definitely stronger with the players we have brought in.
"It will be a tough game. Forfar are a big side and they've got potentially a good side there and the potential to make it very difficult in defence and attack."
Forfar are one of a number of sides in the lower divisions with an artificial pitch and McCoist admits he is not keen on such surfaces.
He said: "There are big concerns.
"I've made my views on the surfaces crystal clear. We don't like them at all.
"But we are very appreciative and aware of how important they are to teams and the communities within their towns.
"We understand the situation. That said, it doesn't mean to say we are happy playing on them.
"I didn't think at any time in the 90 minutes against Queen of the South that we looked really comfortable on (their artificial pitch) to be honest.
"They are a fact of life, especially in the lower divisions, and it's just something we will have to continue to handle.
"If you were at our game on Tuesday, you could actually see the players that look slightly more comfortable on it than others.
"We've definitely got boys who don't look anything near comfortable on that surface."