Former West Ham winger Joe Cole insists official Felix Zwayer has had an awful game, even before sending off Aaron Cresswell on the stroke of half-time.
The full-back was handed his marching orders inside the two additional minutes after tugging Dembele back when he tried to break into the box in the first-half of the Europa League quarter-final at the London Stadium.
The 25-year-old Dembele winked at the camera when it zoomed in after the Hammers were reduced to 10-men as they went into the half-time break goalless.
Hammers boss David Moyes even waited for the referee to voice his anger at the decision, and has been shown a yellow card.