13 minutes.
That's how long it took for the deadlock at Stamford Bridge to be broken between Chelsea and Arsenal - and how long it was until Arsenal fans were screaming blue bloody murder for what they saw as clear foul-play.
The home side took the lead when Pedro's right flank cross was met by Diego Costa, only for his headed effort to smack against the crossbar. The ball looped back into the six-yard area where Hector Bellerin was waiting to head away.
But he hadn't counted on Chelsea's Marcos Alonso thundering in with an emphatic header into the Gunners' net. It was a physical mismatch, but Arsenal fans were livid at what to them was an ill-gotten advantage.
According to the North London contingent, Alonso elbowed Bellerin in the face to get to the ball, and should have been sent off instead of awarded the opening goal. Alas the goal stood and Chelsea took the lead.
That didn't stop Gooners everywhere venting their spleens about the decision...
https://twitter.com/ZeyadBeshara/status/827862545507680257
https://twitter.com/gunnerblog/status/827860365711179777
https://twitter.com/Tolu_Johnson/status/827860629096656897
https://twitter.com/Arsestat_/status/827860624046702593
https://twitter.com/mathis_eric/status/827860618954862592
https://twitter.com/matjumba/status/827860914862964736
https://twitter.com/CallMeSpits/status/827860478999293953
https://twitter.com/JamesTylerESPN/status/827860354738876416
https://twitter.com/SlyThroughBalls/status/827861486399799296
https://twitter.com/rfstokes44/status/827860417099739136
https://twitter.com/Arsenal_LINY/status/827860389979369474
