Diego Costa
Diego Costa has already scored seven goals for Chelsea. Getty

Spanish press have questioned Diego Costa's commitment to the Spanish national team after the striker scored a hat-trick for Chelsea just five days after being withdrawn for the Euro 2016 qualifier against Macedonia due to an injury.

Even though last season the new Chelsea hero snubbed the chance to play for Brazil - where he was born - and opted instead to defend Spain, his performances with Vicente del Bosque's squad have been under increasing scrutiny.

Costa has struggled to make the impact expected with the national team and after five games is yet to score a goal. He was also one of the scapegoats for the Spanish squad's disappointing World Cup campaign. Some pundits say his aggressive attitude doesn't fit at all in the tiki-taka style.

Spanish Daily AS hints that he faked having an injury to pull out of the Macedonia game last week.

The former Atletico Madrid forward played a part during the friendly defeat to France but was withdrawn from the squad the next day due to a hamstring injury.

AS say they then requested from the Spanish Football Federation a medical note signed by a doctor confirming the injury, but they rejected it and let Costa return to West London for treatment.

The questionable part for AS is that just five days after Jose Mourinho handed Costa a starting role against Swansea, the striker looks shaper than ever, eventually leading his side to a 4-2 victory with an impressive hat-trick.

Meanwhile, Costa is being full of praised in the Premier League after an amazing start to life at Stamford Bridge.

Nevertheless, the 25-year-old forward has scored seven goals in four games for the Blues since his £32m summer move from Atletico Madrid, having netted at least a goal in each of their Premier League games.