AC Milan have paid tribute to "unforgettable" former owner Silvio Berlusconi following his death at the age of 86 on Monday.

Berlusconi bought his hometown club in 1986 and turned the struggling side into one of football's most successful clubs.

Under his leadership, Milan won five European Cups, as well as eight Italian league titles.

In 2017, he sold the club to Chinese investors for 740m euros (£628m).

Fifa president Gianni Infantino described Berlusconi as a "visionary".

Milan tweeted: "Deeply saddened, AC Milan grieves the passing of the unforgettable Silvio Berlusconi and wishes to reach out to the family, associates, and most cherished friends to share our sympathies."

The former Italian prime minister returned to football less than 18 months after selling Milan when his holding company, Fininvest, bought 100% of shares in third-division side Monza in 2018.

Berlusconi and former Milan chief executive Adriano Galliani guided the club to Serie A for the first time in their 110-year existence.

A Monza statement read: "Forever with us. Adriano Galliani and all AC Monza mourn the loss of Silvio Berlusconi.

"A void that can never be filled, forever with us. Thank you for everything President."

Real Madrid manager Carlo Ancelotti, during his playing career, helped Milan lift their first league title of the Berlusconi era in 1988 and returned to manage the club from 2001 to 2009.

The Italian was criticised by Berlusconi during his early seasons for his supposedly defensive tactics but would go on to win the Champions League twice, the Coppa Italia and secure the Serie A trophy with an Italian record 82 points from 34 games.

Ancelotti wrote on Twitter: "Today's sadness doesn't erase the happy moments spent together.

"There remains infinite gratitude to the President, but above all to an ironic, loyal, intelligent, sincere man, fundamental for me as a footballer first, and then as a coach. Thank you President."

In a statement, AC Milan's city rivals Inter said: "He has left an indelible mark on the history of our country. The challenges between Inter and his Milan have made the city of Milan the heart of world football."

Berlusconi was a controversial figure and often complained of victimisation - particularly by prosecutors in his native Milan - once claiming to have made 2,500 court appearances in 106 trials over 20 years.

Charges over the years included embezzlement, tax fraud and false accounting, and attempting to bribe a judge. He was acquitted or had his convictions overturned on several occasions.

In a tribute posted on Instagram on Monday, Infantino said: "In terms of football he had foreseen everything long before the others, and in fact he became the most successful president in the history of (AC Milan).

"Recently, as owner of Monza, he fulfilled another dream, because in dreams size doesn't matter. They can even be contained within a small town.

"I want to remember him just like that, like the person who - in our beloved sport - dreamed and then transformed those thoughts into reality."