An early second half winner from former United striker Josh King condemned Louis van Gaal's injury hit side to a third league loss of the season on the South Coast.
Bournemouth came into the game buzzing with confidence after their shock win at Chelsea last week and this was a belief that was only heightened when the hosts went ahead in only the second minute.
Junior Stanislas- a constant threat to the United defence all day- whipped in a wind assisted corner that looped over the stretching David de Gea and into the top corner as the Vitality Stadium erupted.
The visitors response was good and the Reds almost equalised a few moments later as a superb double save from Cherries stopper Artur Boruc kept out the excellent Marouane Fellaini and the recalled Paddy McNair.
Anthony Martial then spurned another golden opportunity when sent on through on goal by an errant Bournemouth backpass, but his effort was poor and he could only drag the ball wide.
De Gea then made partial amends when he smothered at the feet of Stanislas when the forward was clean through, but United then deservedly and decisively pulled themselves level.
It was a scrappy goal in keeping with much of the game as Fellaini pounced on a loose ball to bundle it in past Boruc, but the Reds joy was short-lived as we picked up yet another injury as Jesse Lingard left the field clutching his thigh.
United's travelling army may have experienced a deflating sense of deja vu as we again started slowly and- for the fourth time in two games- conceded again from a set-piece.
King- the former Academy graduate under SAF- did the damage from a corner when he escaped Daley Blind inside the area to prod home a low finish under De Gea.
Boruc saved well from Fellaini and then had the rebound blocked, but in truth Bournemouth should then have extended their lead and ended the match as a contest.
Substitute Glenn Murray was put through on goal by Dan Gosling, he rounded McNair and looked poised to score but lifted the ball over the bar before he then went close again from close range moments later.
Martial flashed a left-footed drive off target but United never looked like finding a leveller as Eddie Howe's side held on for a second famous win on the bounce and leave us, worryingly, without a win in five.
Overall team performance: 6/10
United Faithful Man of the Match: Marouane Fellaini