Diego Costa has been suffering from a mystery illness that had the striker visit the hospital on his return from the Spanish national side, after Chelsea officials were left angry at the condition of their star player after representing his country in the international break, according to the Telegraph.

Chelsea face a tricky trip to Old Trafford on Sunday, and the club will be pushed to their limits by a United side who are improving their form in the season. Louis van Gaal is under tremendous pressure after a disappointing start to the season, and the fans will expect the new manager to show his skills and take United to a title challenging stage.

Costa has settled into life in the Barclays Premier League sooner rather than later, and the player is the club and league’s top scorer so far with Manchester City’s Sergio Aguero closing the gap fast enough.