Six matches into the tournament, Northants have picked up a solitary point from last Friday's rained off clash at Worcestershire Rapids, losing all five of their other fixtures.
Their latest loss was a 34-run defeat at the hands of Leicestershire Foxes on Sunday, and it means the team is going to have to be near perfect from now on in with just eight North Group matches remaining.
This week is going to be pivotal to the Steelbacks' fast-fading hopes of qualifying for the knockout stages, with Wednesday's showdown at Durham followed by a home clash with Lancashire Lightning on Friday and then a trip to leaders Yorkshire Vikings on Saturday.
Northants are currently eight points adrift of fourth-placed Durham, with both sides having played six matches, and Ripley knows only a win will do in the north east.
"We are in the last-chance saloon now, and we all know that," said the Steelbacks head coach.
"We keep saying to the players after every game that I feel we are capable of going on a run, and I do still feel that.
"But by the time you have thrown in a wonder-performance from somebody in the opposition or a rained out game, we have pretty much got to win 90 per cent of the games we have left.
"There is no wriggle room now."
It has not been the T20 campaign that Ripley was anticipating, especially as Northants have enjoyed such a good LV= Insurance County Championship season, and he is making no excuses.
"We haven't played well," said the head coach.
"We have had things that haven't gone in our favour here and there, but the fact is we haven't played well enough.
"That said, we do still have the chance to show we do have some good players, and that we can play better."
The match at Durham is going to be a tough one for the Steelbacks to negotiate, especially as they have the services of England all-rounder Ben Stokes at their disposal.
They have Australian batsman Cameron Bancroft in their ranks, and also signed former Northants skipper Kyle Coetzer on emergency loan, but the Scotland international is unlikely to play.
Durham go into the Steelbacks encounter having won four of their six matches, losing only to Notts Outlaws, and Ripley is expecting a different kind of T20 encounter on a ground that has a larger than average outfield.
"Durham at their place tends to be a very different fixture to when we have them at home, when there is a small field and it is a bit about boundary hitting," he said.
"You go to Durham, the field is big and there is a lot of running between the wickets, taking a lot of twos, and a lot of strategic bowling into the wicket.
"We are always prepared for that, but we haven't always adapted well enough, so it is another challenge for us to do that, and we are looking forward to it.
"We are looking forward to getting off the mark, and the match at Durham gives us the opportunity to do that.
"We are as ready as we can be for the challenge."
Northants Steelbacks squad v Durham: Rossington, Buck, Curran, Glover, Heldreich, Keogh, Nabi, Parnell, Sanderson, Taylor, Thurston, Vasconcelos, G White, Zaib