Having been deservedly beaten by Brighton last week, United sought to make a quick start but it was Brentford who found early joy as the visitors’ defence crumbled in spectacular fashion against their high-pressing hosts.
Brentford produced a stunning first-half performance as they scored four goals in the first 35 minutes to condemn Manchester United to a humiliating defeat at Gtech Community Stadium.
Josh Dasilva put the hosts ahead when his strike from distance somehow eluded United goalkeeper David de Gea.
Mathias Jensen doubled the lead after dispossessing former Brentford player Christian Eriksen, with Ben Mee and Bryan Mbeumo goals putting Thomas Frank’s side four up during an incredible first half in which they dismantled United in stunning fashion.
The defeat is United’s seventh in a row on the road – their worst run since 1936 – while it is the seventh time they have conceded at least four goals in a league game since the start of last season.