Defeat to Tottenham at the Madejski Stadium, courtesy of Robbie Keane scoring the only goal of the game in the 16th minute, dropped the hosts in the bottom three with one match left.
The game is against Derby but three points are not guaranteed as Reading have not scored in six matches.
Coppell said: "People remind you all the time that you haven't scored for so long and there is the confidence factor.
"Now it's win or bust next week, we have to get a result to give ourselves a chance.
"It doesn't matter who we play we have to win, we've lost the habit of winning football matches."