Diego Costa appears to still be causing trouble at Chelsea, despite having been sold to Atletico Madrid. According to reports, David Luiz believes that his current spat with Chelsea manager Antonio Conte can be traced back to his former team-mate. The Brazilian defender was dropped from the squad for the match with Manchester United on Sunday. It followed a dressing down from Conte during a meeting last Thursday, during which the Italian picked on Luiz for his performance in the recent Champions League defeat to Roma. After the 1-0 win over Manchester United, Conte failed to give any guarantees over the defender’s future at the club.