The Red Devils recorded just their third Premier League win of the season as they emerged 2-1 winners at Sunderland on Saturday evening.
United had lost three of their opening six league games before Saturday’s win at the Stadium of Light.
And striker Rooney says that the players are to blame for United’s recent struggles under their new manager.
“Obviously the manager is under a bit of pressure,” Rooney said.
“We know as a team it’s us who have let him down. We have to pull together for the manager and show the sort of fight we have done here and we’ll be fine.
“It’s a new manager with different styles and we have to adapt to them. We need to do better for him than we have been.”
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