The former Manchester City player managed to get on the scoresheet at the Stadium of Light last night, but the Black Cats eventually succumbed to a 2-1 defeat against West Ham United.
"We had some good chances, but we just can't seem to score," Johnson told The Shields Gazette. "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've got some tough ones coming up. We have to capitalise on the games at home, which we haven't done all season.
"We've got four home games left and I think if we win all four, we've got a chance. There's still eight games and points to play for."
Sunderland are second from bottom in the table, four points adrift of safety.