Manchester United players lost faith in former manager Jose Mourinho, according to Newcastle United captain Jamaal Lascelles.
United have won three straight games since Mourinho's sacking.
Ahead of Wednesday night's clash with United, Lascelles said: "They probably needed that (a change at the top). They have world-class players on big wages who have done it for their countries and for other teams, but have not done it for Manchester United.
"Some players can only play for certain managers and that reaction you get from the players.
"Maybe (Solskjaer) might be the difference in getting the best from those players. They have a lot of quality. It will be an exciting game."