The Red Devils fell from their perch atop the Premier League last term, where David Moyes took over when the side were newly crowned champions, only to lead them to a seventh-placed finish.
Louis van Gaal has since replaced the Scotsman, but he too has struggled to get the best out of the team, who have won just one of their opening five league matches, while they most recently suffered a shock 5-3 defeat to newly promoted Leicester City.
The English titans had also slumped to a 4-1 loss against League One side MK Dons in the second round of the Capital One Cup, but Rooney is refusing to give up hope of a comeback, and predicts the Old Trafford outfit will once again rise to the pinnacle of world football.
Rooney wrote on his Facebook page: “There seems to be a lot of people who have written us off because of Sunday’s result but I don’t see it that way.
“When I look around our dressing room and see the quality we have and the manager’s unbelievable attention to detail, I have no doubts this team will be successful.”