Angel Di Maria cost Manchester United a British record transfer fee when he moved to Old Trafford last month, but reports suggest that the Premier League giants could owe more money as part of the deal in the future.
The Red Devils shelled out an eye-watering £59.7 million to bring Argentine playmaker Di Maria to the Premier League from Real Madrid towards the end of the summer transfer window, with the 26-year-old having slipped down the established pecking order in La Liga following the respective signings of World Cup winner Toni Kroos and Colombian sensation James Rodriguez.
Ballon d'Or clause
And according to The Daily Telegraph, Manchester United could have to play an extra £4 million on top for Di Maria - dependent entirely on whether or not he manages to win the prestigious FIFA Ballon d'Or award in the coming years.
The same source believes that such an unusual contractual clause was included at the behest of Real and Di Maria's own camp, with Ed Woodward and co presumably seeing no problem with it due to the rather trivial sum involved and the heroics that he would have to perform in England to beat the likes of Lionel Messi and former teammate Cristiano Ronaldo to the honour.
Those two aforementioned superstars have largely dominated the voting since the Ballon d'or was merged with the FIFA World Player of the Year gong four years ago, Messi - who also won the award in 2010 - triumphing over his great rival in 2011 and 2012 before Ronaldo finally turned the tables in 2013.
Di Maria has made just one appearance since completing his eye-catching transfer to Manchester United - a largely impressive display from the former Benfica man in an otherwise disappointing and flat 0-0 draw with newly-promoted Burnley at Turf Moor.
He also got fans suitably excited for what is to come on international duty this week, providing three wonderful assists and a goal of his own as Argentina romped to victory over Germany in a repeat of the World Cup final in Düsseldorf on Wednesday evening.