Tensions are always pretty high after Chelsea play Arsenal, regardless of the result.
Nevertheless, when Patrick Bamford - who, believe it or not, is still technically a Chelsea player - decided to innocently like a few Instagram posts, he had no idea of the backlash it would cause.
Football fans are a loyal bunch and expect to see the same dedication from their players. Even though Bamford is currently on loan at Burnley, Chelsea supporters were still disappointed to see him appreciate various Arsenal players celebrating the 3-0 victory over his parent club on Saturday.
Hector Bellerin and Mesut Ozil both updated their Instagram profiles with images captured during and after the victory at the Emirates Stadium and a few eagle-eyed fans spotted Bamford 'liking' the posts.
The young forward was then inundated with requests for an explanation for the activity on the popular social media website.
And he has duly responded on Twitter: "Wth regards 2the Instagram pics I liked, was only liking my friends pics as I've done many a time. No shade or disrespect intended. Sorry!"
Fair enough, he has apologised. But the supposed friendship with Ozil and Bellerin seems much harder to believe, as a few supporters pointed out:
Bamford looked like a fantastic prospect in the Championship just a couple of years ago but his most recent loan spells in the Premier League haven't gone to plan.
A lack of minutes on the pitch and goals scored has seen his stock decline and he is yet to make a senior appearance for the Blues, despite joining from Nottingham Forest four years ago.
Now at Burnley, this might be Bamford's last chance to prove he can cut it in the English top flight.
Even if he does, it will take some doing to overtake Diego Costa and big summer signing Michy Batshuayi in the pecking order at Chelsea and at this stage, a permanent move away from Stamford Bridge looks inevitable.