Manchester United may have to wait until Jurgen Klopp and Pep Guardiola leave Liverpool and Manchester City respectively before they win another Premier League title, according to Gary Neville.
Not since legendary manager Alex Ferguson's final campaign at Old Trafford in 2012-13 have United lifted the top-flight crown, finishing in the top two just once since then.
Despite an upturn in form in the second half of last season, Ole Gunnar Solskjaer's side ended 33 points behind dominant champions Liverpool and 15 points adrift of runners-up City.
Klopp ended Liverpool's 30-year wait to finish top of the pile in English football, coming on the back of successive triumphs for City under Guardiola, including a record points haul in 2017-18.
Former United full-back Neville is confident United will add a record-extending 21st title to their list of honours, but only once there has been a changing of the guard at the Etihad Stadium and Anfield.
"The one thing I can guarantee you is that United will win again," he told The Mirror.
"That might not be this year or next year, but it will be amazing when they win again, and the longer it builds up, the greater the actual feeling is when you do it.
"I'm not sitting here, as a United fan, thinking, 'We must win the league this year'. Yes, we'd like to, but you know when it's your time and it's not yet.
"It will be, maybe, when Klopp and Guardiola leave Liverpool and City - hopefully in the next couple of years!
"That will be the chance, as they're two outstanding managers who have built really good teams, but they'll leave in the next one, two or three years.
"That will be the point when United can come back in and capitalise - I'm sure Chelsea are thinking that way as well.”
Neville has been critical of United's transfer business during the close season, having only brought in midfielder Donny van de Beek from Ajax so far.
United have been strongly linked with Borussia Dortmund's Jadon Sancho all window, but Neville suggested four more signings are needed if his old club are to challenge for the title this term.
"That's out of the question for me, if you ask me today, with the squads that they've got," he said.
"If United were to sign two outstanding forwards, an amazing centre-back and a fantastic left-back in the next three weeks, then maybe."