The Light Blues crashed to a 2-1 defeat to title rivals Hearts on Sunday as they got their bid for the second tier crown off to the worst possible start.
Just days after they struggled to overcome Hibs in the Petrofac Training Cup, Nicky Law's injury-time leveller proved in vain for the Gers as Osman Sow added to Danny Wilson's opener to clinch the win for the Jambos.
Rangers were booed off at the end of another poor performance as the pressure mounted on McCoist and his players once again.
A trip to Falkirk on Friday night gives the second-tier title favourites a quickfire chance to get back on track and silence the doubters.
And McCoist is determined to spark an improvement in his side's fortunes against Peter Houston's side.
McCoist said: "It's absolutely vital we react quickly. That's the first defeat we've had in the league for a long, long time and it's not a good feeling or a nice one.
"I don't have any doubts the players will be experiencing the same feelings we are and we aim to put that right.
"We've lost three points when we probably should have taken something from the game. We're extremely disappointed, but hopefully we can make amends on Friday night."
It has been a low-key start to the campaign for Rangers as they have toiled against Hibernian and the Jambos in their opening two competitive fixtures.
Falkirk will provide another stern test for the champions and have been tipped by many as potential promotion contenders themselves this term.
But McCoist insists he has not been taken aback by the challenges Rangers have faced in the opening fortnight of the campaign.
"In terms of the opposition, we've not been surprised by the toughness of the fixtures we've had so far," he told rangers.co.uk
"We knew the Hibs game and the Hearts one would be a real step up in standards of opposition from what we have been playing. They've not surprised us."