London - Combining predatory instincts with a street fighter's approach to duelling with defenders, Diego Costa has emerged as the unapologetically snarling face of Jose Mourinho's hugely successful Chelsea overhaul.
Prised away from Atletico Madrid for $49 million by Mourinho, who surely recognised a kindred spirit in the fiercely competitive and occasionally spiteful Brazil-born Spain international, Costa has been everything the Chelsea manager could have dreamt of in an explosive debut season in English football.
If the bruising Didier Drogba was the blunt instrument Mourinho favoured to bludgeon opponents into submission in his first spell as Chelsea boss, in Costa, likely to be the key figure in Sunday's League Cup final against Tottenham at Wembley, he has found an even more effective weapon.