Barcelona have opened the battle to sign  Chelsea forward Willian after launching an initial £50 million bid. 

The Daily Mail reports that Willian’s representatives have been in Barcelona to begin negotiations with the Catalan side over the past week.

Chelsea are understood to have rejected the initial bid, and will hold out for more, mindful that Manchester United may be willing to offer a more lucrative deal.

Manchester United manager Jose Mourinho is keen on a re-union with his former star, and is reportedly to offer Chelsea cash plus Anthony Martial in order to bring the Brazilian to Old Trafford.

The Portuguese spoke highly of the Brazil international earlier this year following United’s 2-1 win over Chelsea in which Willian was on the scoresheet.

Mourinho said: “Do you want to talk about Willian? Top, cream of the crop, he’s amazing.”

Willian made 55 appearances in all competitions for the Blues last term, winning the club’s Player of the Year award for his 13-goal haul, however publicly fell-out with manager Antonio Conte following the FA Cup final in May.

The 29-year-old was left out of the Italian’s starting line-up for the victory over Manchester United at Wembley, coming on in the 89th minute as a only a late substitute and subsequently posted a picture of Chelsea’s squad celebrating the win, blanking out Conte with a series of trophy emojis.