Costa has been in fine form for Antonio Conte's Chelsea this season.
The Spain international has 15 Premier League goals so far, and will be looking to add to his tally against Arsenal today (12.30pm).
And Fabregas has now heaped praise on Costa.
Cesc Fabregas has heaped praise on his Chelsea team-mate Diego Costa
"Obviously you know Diego has been a very important player for Chelsea and for Atletico Madrid in the last five, six years and he’s been one of the top strikers in the world," Fabregas told Chelsea TV.
"I have a fantastic connection with him, not just only on the pitch but also off the pitch.
"I consider him my friend, he’s a great guy.
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Fri, February 3, 2017
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Chelsea have been training hard ahead of their clash with Arsenal
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Chelsea star Diego Costa has 15 Premier League goals this season
"Also, on the pitch I like to play with winners and he’s definitely one of them.
"Of course, if he is a guy that you understand so well that when you pass him the ball he scores a high percentage of your passes, then fantastic.
"We played against each other in Spain but we didn’t really know each other and I remember on our debuts actually we had our first connection and we scored a goal."