When Mason Mount scored to put Manchester United ahead against Brentford on Saturday night, Erik ten Hag was delighted. Steve McClaren’s face said it all, however. Eyes wide with shock, the former England boss couldn’t believe his side had broken the deadlock at the death. The goal looked as though United would be leaving Brentford, the home of their memorable 4-0 humbling last term, with all three points. It was undeserved and bitterly cruel for the hosts, who had dominated proceedings. Make no mistake about it, with better finishing, they could have inflicted another battering. Yet Ten Hag a…