The man who guided Yeovil Town to the Championship would not have accepted the manager's role at Whaddon Road unless he thought survival was achievable.
Having been unveiled as Cheltenham's new boss on Monday evening, Johnson will meet the players at the training ground on Tuesday morning before starting preparations for Friday's vital match at York City, who are four points above the 23rd placed Robins.
With seven matches remaining, former Yeovil Town and Bristol City manager Johnson admitted it would be among the greatest achievements of his long career if he could steer them to safety.
"Cheltenham are a club that should be in the Football League," he said. "This is a very unusual situation, coming in with seven games left, but a decision had to be made and I was asked if I could help.
"It's a club I have always liked and it's so important that we stay up. I'll do my best to achieve that aim.
"We are at the business end now with seven 'play-off' games and Friday at York is a key match."
Johnson spent Monday evening analysing videos of Cheltenham's recent fixtures, having been at the recent games against Portsmouth and Exeter City in person.
"I have a good idea of the squad and I know most of the players," he said. "Some of them have a reputation for certain things, some good and some bad, but everyone starts with a clean sheet.
"We have to pick the best team to win a football match and motivate them.
"The mission statement is to keep Cheltenham in the Second Division and if I didn’t think there was a chance I wouldn’t be here now and the board wouldn’t have taken the chance on me.
"It’s the club's fourth manager this season, but the third manager, Russell Milton, is still here and the staff are still intact – that was important to me and the board.
"It will be 100 per cent up there with anything I have achieved if we can keep Cheltenham out of trouble."
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