Chelsea lead Arsenal 1-0 at half time in a massive London derby at Stamford Bridge.
Marcos Alonso’s header is the difference as the Spaniard reacted quickest to Diego Costa’s initial header crashing off the bar.
As he headed home Alonso’s elbow clattered into Hector Bellerin’s face, leaving many calling for a foul, but referee Martin Atkinson let the goal stand and Bellerin was subbed out looking dazed.
Click play on the video above to watch Alonso’s controversial header as Chelsea are 45 minutes away from going 12 points clear of the Gunners.
Plus, hit the link above to stream the game live.