Costa sealed a £32m move to Stamford Bridge from Atletico Madrid in July 2014, and his introduction certainly left his new captain in awe:
‘The last time John Terry, Gary Cahill, Branislav Ivanovic and Nemanja Matic had seen Costa was at Stamford Bridge, as he shook their hands and left the pitch, on his way to the Champions League final after Atlético Madrid’s 3-1 victory over Chelsea.
‘Oscar introduces Terry, Cahill, Ivanovic and Matic to Diego Costa. They shake hands, then Costa straightens up and delivers his pitch in heavily-accented halting English.
‘I go to war. You come with me.’
Guillen goes on to write that there were a few laughs from the Chelsea players, but Terry and co shared a look that suggested Jose Mourinho had found the centre-forward the club were itching for.
Costa certainly lived up to his promise of ‘war’ in his debut Premier League campaign, regularly ruffling the feathers of fearful defenders.
He scored 21 goals in all competitions, with only an end of season injury banishing his chances of pipping Sergio Aguero to the Golden Boot.