Rafa Benintez has told his Newcastle United players to "wake up".
Benitez's second-placed side were beaten 2-1 by Sheffield Wednesday at Hillsborough yesterday.
Brighton and Hove Albion lead United by two points at the top of the Championship.
Third-placed Huddersfield Town, beaten by Nottingham Forest, are 10 points behind Newcastle, who take on Leeds United at St James's Park on Good Friday.
"What we have to do is be sure that we wake up, that we are ready for the next game," said United manager Benitez.
"We have five games to play. We are in a good position, and I told the players that I was disappointed, but at the same time that they must keep their heads up and start working because we have to do better for the next game."
Newcastle made a series of defensive mistakes at Hillsborough, where Tom Lees and Steven Fletcher netted second-half goals for Wednesday.
Jonjo Shelvey scored for United during a late rally.
"It's a big mistake against a good team," said Benitez. "This game before, you know it will be tough, and I think we started the game with three mistakes from us."