Brentford boss Thomas Frank called Manchester United "unbelievably lucky" to beat the Bees on Wednesday night.
Ralf Rangnick's side scored three times in the second half through Anthony Elanga, Mason Greenwood and Marcus Rashford as they shrugged off a disappointing first period, during which David de Gea was able to keep Brentford at bay.
The Spanish goalkeeper made smart stops to twice keep out Mathias Jensen as the Bees attacked well in the first period, and ultimately Frank's men only had Ivan Toney's late consolation goal to show for their efforts.
