The Black Cats remain four points adrift of safety following Monday night's 2-1 home defeat by West Ham and now face an almighty battle to maintain their Premier League status with eight games left.
It looks an impossible task with visits awaiting Gus Poyet's men to Tottenham, both Manchester teams and Chelsea.
Johnson said: "It's another game down. We keep saying 'This is the game, this is the game' but time is running out now. The games are running out and we have got some tough ones coming up.
"We have to capitalise on the games at home, which we haven't done all season. We have got four home games left and I think if we win all four, we have got a chance. There are still eight games and points to play for.
"We have just got to stick together and keep trying to do the right things. We can't get cut adrift because it's difficult then. Any of the games away from home against the top six are difficult, but we tend to perform better against those top teams."
Three of their last four home games look winnable on paper - their next outing on Wearside brings Everton to the north east with Cardiff, West Brom and Swansea to follow - but they have managed to take three points on home turf only once in nine attempts in the league.
More worryingly, only one of their six wins has come against a team currently occupying a place in the bottom half of the table, a 4-1 victory at Fulham in January.
Their loss to West Ham this week was a huge blow to their hopes of survival and Poyet was still fuming over their failure to be awarded a penalty when Kevin Nolan appeared to handle inside the box.
The Sunderland head coach said: "The penalty, massive - that could be the difference between staying up or going down."
With the players next heading to White Hart Lane for Monday's Sky live game, Johnson reflected on his team's inability to perform for the full 90 minutes.
Johnson, introduced from the bench against the Hammers with 37 minutes left and scored their consolation goal, added: "We go into these games knowing they are going to be difficult, and maybe we just try too hard.
"We should have definitely got something out of the game (against West Ham) after the second half. But it wasn't meant to be again. It's the same old story, isn't it?
In the second half, we were definitely the better team. But you need to put those chances away."