Chelsea striker Diego Costa has refused to rule out a move back to former club Atletico Madrid, as the striker’s future at Stamford Bridge remains unclear. The Spanish striker, who was integral to the West London side’s championship winning team last season, has struggled to reach the same levels of performance this time around. He was imperial in his final season at Atleti, dazzled in is first in England but longs for an end to the nightmarish second season at Chelsea. But would you say Diego Costa has earned the 'World Class' tag nonetheless? https://www.instagram.com/p/_HIyguMfDJ/