The Reds were 3-0 up at half-time thanks to goals from Marcus Rashford and Alejandro Garnacho, either side of Antony's penalty.
Garnacho grabbed his second, from Christian Eriksen's excellent pass, and Rashford soon followed suit, with another clinical finish, thus ensuring new territory for United under the boss.
It was the first time we have hit five goals in a single game since Ten Hag took over and there was more to come.
Eriksen, who already had that assist to his name, smashed home a brace to cap a fine team performance, with the floodgates well and truly open.