Everton’s great big defenders allowed Schade’s long throw to bounce, Bryan Mbeumo headed against the bar from close range and Wissa reacted quickest to nod in from on the goalline.
In first-half stoppage time, O’Brien was among the burly Toffees defenders who failed to deal with a long throw and was then unable to stop Yoane Wissa giving Brentford the lead.
For all the silky skills of Kevin Schade and Mikkel Damsgaard, and despite a number of decent openings, the hosts had not forced Jordan Pickford into a meaningful save before Beto fluffed two big chances.
Wissa had a goal ruled out for offside after Keane Lewis-Potter opted to pass rather than shoot after Damsgaard’s luscious pass.
Yet the Bees will also feel that they missed a big opportunity to put themselves right back in the mix in the top half of the table where every point counts.