Gary Neville believes Manchester United will not challenge for the Premier League title until 2021/22 at the earliest.
The Red Devils have not won the league since Alex Ferguson's final season before retirement in 2012/13.
Saturday's 2-1 loss to Crystal Palace means Ole Gunnar Solskjaer's side are already five points adrift of first place this term.
And Neville, who won eight Premier League titles at Old Trafford, believes it will take some time before his former club are ready to compete at the top.
"It may seem like too far into the distance but I would suggest four or five transfer windows to get things absolutely right and get back to the type of squad he would want to challenge these Liverpool and Man City teams," he told the Gary Neville podcast.
“I've said before, he's got to be ready, not at the end of this season, not next season, but the one after, to challenge for the Premier League title. Potentially when Pep Guardiola has left Man City, or Liverpool have had another round of recruitment and another set of players in... Ole has got to be ready to pounce.
“It's a long-term thing, there's not going to be a quick fix or magic wand from any manager. United have tried David Moyes, they've tried Louis van Gaal, they've tried Jose Mourinho - all proven - and Ole Gunnar Solskjaer is going down the long road, not the quick path.
"There's no shortcut - there never is - and for me, it's now about making it through these difficult moments, like losing to Crystal Palace and you feel like the world is going to fall in but people must remain patient.
"I want to see the nonsense go, the speculation that players want to go, I want to see the disciplinary issues or the little tit-for-tat stuff over the last two or three years where there have been fallouts, I want to see that go and the leaks. I want to see a team building slowly."
United will be looking to bounce back from their defeat by Palace when they travel to Southampton this weekend.
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