A midweek victory over Chelsea had offered cause for optimism but in-form Bournemouth exposed just how far Ten Hag’s United have fallen behind this season.
The Dutch coach looked forlorn as he watched on in the teaming Old Trafford rain as his shambolic side were comprehensively outplayed and fortunate not to lose by more.
They were loudly booed off at the final whistle although many fans had long since trudged off.
United’s fourth home league defeat of the season failed to inspire much hope ahead of next week’s must-win game against Bayern Munich in the Champions League.
They took the lead after five minutes when Lewis Cook burst through the United defence and squared the ball for Solanke to finish tidily.
United were finally beginning to threaten an equaliser in the second half but were floored by two goals in five minutes for Bournemouth — Billing and Senesi both scoring with thumping headers from Marcus Tavernier deliveries, as United’s defence went AWOL.
Bournemouth hunted for more goals and were denied a very late fourth when Dango Ouattara bundled through and netted but his effort was ruled out for handball after a VAR check.
Bournemouth’s victory did not flatter them in the slightest and the south-coast club are up to the relative safety of 13th place. For sixth-placed United it remains one step forward and two steps back as they undid all the good work of Wednesday’s impressive victory over Chelsea.