Cristiano Ronaldo has criticised Manchester United manager Erik ten Hag and said the club must "rebuild everything" in order to compete for football's biggest prizes again.
The Dutch boss is under pressure after United's eighth-placed finish last season - their lowest in Premier League history - and two defeats in their opening three games at the start of this campaign.
And Ronaldo, who had two spells at the club before leaving for Saudi Arabian side Al-Nassr, questioned Ten Hag's mentality.
"The coach says they cannot compete to win the [Premier] League and Champions League," he told the Rio Ferdinand Presents podcast, external, which comes out on Thursday.
"As Manchester United coach, you cannot say that you're not going to fight to win the league or Champions League.
"Mentally [you can] say maybe we don't have that potential, but I cannot say that. We're going to try, you have to try.
"What I wish for Manchester [United], it's what I wish for me - [to be] the best team they can.
"I love that club... I'm not that kind of guy that forgot the past."
In his six-year first spell at United, Ronaldo won three Premier League titles, the Champions League, two League Cups and an FA Cup - as well as the Fifa Club World Cup and Community Shield - before transferring to Real Madrid in 2009.
He re-joined United from Juventus in August 2021 and scored a total of 145 goals in 346 appearances for the club before he moved to Al-Nassr in December 2022.
Just a month earlier, Ronaldo had told presenter Piers Morgan he was being "betrayed" and pushed out in a controversial television interview.
And speaking to former United team-mate Ferdinand on his podcast, the Portugal forward said there had been "no evolution" following former boss Sir Alex Ferguson's retirement in 2013.
United have not won a Premier League title since then, but co-owner Sir Jim Ratcliffe wants to restore them to their former glories after purchasing a 25% stake in the club and his Ineos team taking over football operations.
Ronaldo added: "They need to rebuild everything, in my opinion.
"The club needs time to rebuild because it's still one of the best clubs in the world, but they need to change. They understand that this is the only way.
"This is why they show, they start to change again, the structure of the club, the infrastructures and everything. The owners of the club are investing in the training ground so I'm happy [because things are changing].
"I believe that the future will be bright. I believe, but they don't depend only on the talents. They have to rebuild from the bottom. If not, they cannot compete. It will be impossible."
Ronaldo, however, has praised the club's decision to recruit another former team-mate Ruud van Nistelrooy to Ten Hag's backroom staff.
"If Ten Hag listens to Ruud, maybe he can [help himself]," he added.
"I think it can help a lot because he knows the club and the club should listen [to] the guys who were there.
"You [Rio] or Roy Keane or Paul Scholes or Gary Neville [or] Sir Alex Ferguson. You cannot rebuild a club without knowledge - not guys who work in [the] office.
"The people who understand the football are the people who were there in the dressing room. They know how to deal with the players.
"So I believe that Ruud is going to help because he was inside the club. He knows the club, he knows the fans. If the coach listens to him, I think they can improve a little bit the club."