I'm very very much looking forward to referee report, how do you show red to someone and no one knows why? Did Gabriel do something sneaky? But all images and reactions show no one knows what gave him the red except they Costa cried about it after both got yellow? Most likely seems to be Costa cries about Gabriel backing into Costa or heel stamps him, but pretty much BS at best. Costa pretty much is getting rewarded for provoking nonstop.
Also what kind of loser leadership does these two teams have on the pitch? No one separates them when they are super heated and fighting verbally nonstop after they got yellow, only when Gabriel gets red does the little kid Bellerin tell Him to go off, otherwise nothing from either teammates.