Roberto De Zerbi, Marseille's manager, has issued a warning to forward Mason Greenwood following his arrival from Manchester United.

De Zerbi said that during their initial phone call, he warned the England star not to take Marseille lightly.

"Greenwood was the first player I called. "I spoke with his father, who must be my age," De Zerbi told L'Equipe.

"I warned him about the club's demands, telling him that 'OM is OM'.

"He replied: 'I remember the historic OM, which played in European Cup finals'."