Ibrahimovic linked up with Guardiola at Barcelona in 2009, joining the Catalan club from Inter Milan in exchange for Samuel Eto'o and a fee of around €60 million.

However, despite scoring 21 goals in his debut season at the Camp Nou, the Manchester United striker's relationship with Guardiola deteriorated throughout the campaign.

In his 2011 book, "I am Zlatan," the 36-year-old revealed things hit an all-time low after Barca's Champions League elimination to Inter --- who were managed by Jose Mourinho at the time -- when he called Guardiola a "spineless coward."

And Ibrahimovic told Sky Sport Italia: "The first six months were perfect, then the manager changed system, tactics and it didn't work for me. I went to talk to him. I'm here to talk, if you think it's for another reason then we can't talk.

"I said: 'I believe that you are sacrificing some players for one player, [Lionel] Messi.' He said: 'I don't think this is the case but I understand what you say. I will take care of it, no problem. I will solve everything.' I thought it would be OK.

"The following game I was on the bench. I don't say anything, I work. Second match, bench again. I thought he solved it well and he was not talking to me or explaining. Third match, bench. Then the fourth match comes and bench again.

"I think something is strange. From that moment he stopped talking to me, looking at me. I go into a room and he walks out of it. He was not a bad person, but the most immature [coach] I've had because a man solves his problems."

Ibrahimovic left Barca in 2010 for AC Milan, before going on to join Paris Saint-Germain two years later and then United in 2016.

Asked in 2016 about Ibrahimovic's comments about him in his book, Guardiola said: "Always I was clear [with him]. Whatever I said to him I spoke face to face. I never used the media to explain what I wanted from him on the pitch."