By Editor Wayne Veysey | Former Evening Standard, Press Association and Goal chief correspondent with 17 years experience of breaking big stories, including exclusives like this

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Diego Costa has opened the door to leaving Chelsea as he reveals he still supports former club Atletico Madrid.

The controversial striker has had a difficult second season in England, during which he has been openly at odds with manager Jose Mourinho.

Costa has refused to rule out a return to the club he left for a fee of £35million in the summer of 2014.

Speaking to Spanish radio station Onda Cero on Wednesday night, the 27-year-old: “You never know (about a return to Atletico Madrid), look how well Filipe Luis is doing now.

“Life is full of surprises – I always wish Atletico the best and I always follow them and support them from afar.”

Costa hit the headlines for throwing his bib at Mourinho last month, just days after the pair had a half-time bust-up in the tunnel during the team’s 4-0 win at Maccabi Tel-Aviv.

Costa was demoted to the bench for two matches befere returning to the team on Wednesday night as Chelsea defeated Porto 2-0 to qualify for the Champions League knockout stages.

The striker did not add to his tally of four goals this season but played a key role in Chelsea’s opening goal against the Portugese visitors.

Costa told Onda Cero: “The bib incident is in the past. I made a mistake, but my relationship with Mourinho is amazing and we get on really well.

“There are things you need to control, but the bib thing was an impulse. I have to improve a bit. The start of the season has not been good for me – not in how I have played nor in goals.”

A source close to Costa has told Football Insider that the Spain international could be ready to push for a transfer from Stamford Bridge if there is interest in him from one of the leading Spanish clubs.

One potential avenue is former club Atletico, who could be in the market for a new forward if Antoine Griezmann leaves next year.

Aiming high: Costa threw his bid towards Mourinho after being left on the bench

Aiming high: Costa threw his bid towards Mourinho after being left on the bench

The Frenchman, 24, is being closely monitored by Chelsea on the back of a number of goal-drenched seasons in La Liga.

Griezmann had a £57million buy-out clause inserted in the new Atletico contract he signed in the summer but that figure would not put off the Premier League club.

Chelsea are aware that Costa, who has scored only seven times in 31 appearances stretching back to January, is not entirely content.