As quoted by the Sun, the striker himself said: "I am always very honest with the people around me".
The 26-year-old has scored five goals and has made two assists in 30 appearances in the Premier League in what has largely been a positive first season at Stamford Bridge.
He told Standard Sport: "Diego has been massive for Chelsea this season". We've been there nearly all season, we are showing we want to be there, we're playing very good and fighting for it and that's what we need keep doing.
He added: "Diego has a great personality and is very good for the group".
"Then we conceded and lost a bit of confidence but then we managed the game and scored another with Marcos Alonso".
Rose takes Masters heartache on the chin after epic duel
No one had ever played as many majors as Garcia before winning his first one, so those tears were equal parts joy and relief. Rose birdied to match Garcia, then birdied the par-3 16th only to bogey and remain deadlocked to set up the closing drama.
Costa has certainly not been shy regarding his desire to return to Atletico Madrid in the past and rumours regarding an imminent Chelsea exit intensified in January following a reported disagreement with manager Antonio Conte and fitness coach Julio Tous over a back injury.
"The club do a lot for me, the fans, my team-mates and this is a winning team, which motivates you to be there a long time more. But I'm not saying I'm happy with my life in London, because that is something totally different".
"I think Marcos is playing a really good season and it is great for him to show his quality with the free-kick". It's good to play with this pressure because it means we are fighting for titles and trying to stay up there.
Having been the subject of huge transfer speculation from China, with super-league side Tianjin Quanjian believed to be ready to offer the player a staggering £600,000-a-week salary to make the move to the Far-East, many observers feel that these next few weeks will be his last in the Premier League.