Wayne Rooney has called on Manchester United fans to "be a bit patient" as manager Ole Gunnar Solskjaer looks to guide the club back into the Champions League and challenge for honours again.
Rooney, United's record scorer with 253 goals, is set to face his old club in the FA Cup fifth round when the Red Devils travel to Derby on Thursday night.
The former England captain spent 13 years at Old Trafford, during which he won every domestic honour along with the Champions League and the Europa League.
Rooney, 34, returned to boyhood club Everton in 2017 before embarking on a spell with Major League Soccer outfit DC United.
Having joined Derby as player-coach at the end of last year, Rooney has returned to England to find his old club facing a very different outlook to when he was leading the attack.
However, he feels United are moving in the right direction again and just need time to regain their place at the top of the game.
"It is going to take another two or three years, I believe. The important thing is for them to try and get into the Champions League this year," Rooney said, quoted by several national newspapers.
"It is really tight at the minute. I think that will help them a lot if they can do that – but it is going to take time."
Rooney continued: "The United fans need to be a bit patient with what's going on and let these players try and prove themselves.
"They need to bring some players in, they need to also get rid of some players, and within two or three years they have to be challenging again.
"It's not going to be a quick fix. They have tried that with (Louis) Van Gaal, and (Jose) Mourinho.
"If you look at Liverpool and what they have done, they have built that team, and Man City, (Pep) Guardiola has gradually brought more players in for his way of playing.
"So United have to be patient and try to build a team that will be able to challenge those two."
Phillip Cocu's Derby are 13th in the Sky Bet Championship and while Rooney knows the Rams are underdogs, he believes they can cause his old club a shock.
"It's not a game where we are going to be fearing Manchester United," he said.
"Of course they will be favourites, and they will probably have a lot of possession but we need to keep our discipline and our shape, stay in the game and take our chances."
While enjoying his current role as Derby's 'quarterback' playmaker from a deeper midfield position, Rooney has his eye on a long-term future in the dugout.
"We all get older and you have to move into something different. I can't play forever, so I need to think of my future after my playing days," he said.
"I love the game and I want to stay in it, so this is where I am. I want to learn.
"I think it's a shame when you see great players walking away and not really having a go at management or coaching.
"I'm a player first and foremost and then a coach, to try and learn to help me in the long run."
