Arsenal may not have threatened Chelsea's relative dominance towards the top of the table this season, but there is still a strong rivalry between the two London sides.
And it therefore seems unlikely that any fan of the Blues would be annoyed to see one of their stars hanging out with a player that has just helped put Arsenal to the sword.
On Tuesday night, Chelsea's Willian spent time with Douglas Costa as the Bayern Munich forward celebrated his side's 5-1 win at the Emirates.
Costa played a key role as Bayern thrashed Arsenal 10-2 over both legs, scoring during the away tie to help confirm the north London side's increasingly obvious exit from the competition.