The Cherries were unbeaten on the last four occasions that they'd played the Red Devils, and on their last two visits to Old Trafford, they'd headed back to the South Coast with 3-0 victories.
Bournemouth short on confidence
Without a win in six matches currently, short on confidence and having slid down into the lower reaches of the English top-flight, there was probably no better time for United to play their opponents.
Ruben Amorim's side, for their part, were looking to extend a three-match unbeaten run in the league, and the Portuguese again picked young Ayden Heaven for a third consecutive game - the first time in his career that's happened.
Along with Leny Yoro and Luke Shaw, Heaven made up the 23rd different central defensive partnership to start for United in the Premier League under Amorim.
Antoine Semenyo had scored home and away against Man Utd last season, so despite a poor run of recent personal form, the hosts will have known all about the dangers he possessed given half a chance.
Adams' World Cup hopes could be in tatters
His teammate, Tyler Adams, had been known to be interesting the Red Devils as a potential hire; however, after just five minutes of this game, he sustained a potential cruciate ligament injury that saw him immediately taken off.
If confirmed, that would all but rule him out for the remainder of the league campaign and the World Cup, which would be a huge blow to the USA captain, given the tournament is in his backyard.
United had already had two attempts blocked beforehand, and had another two straight afterwards, before Mason Mount had their first shot on target in the eighth minute.
Another two came before the 10-minute mark, and those six shots were United's most in a Premier League game in that period of time since October 2022, against Tottenham Hotspur (also six).
Diallo makes the breakthrough
It appeared to be only a matter of time before the opening goal arrived, and it came via Amad Diallo in the 13th minute.
The visitors had failed to win any of their last four games when conceding first, whilst United hadn't lost any of their last 11 when scoring first, and despite having a double pivot sat in front of their back four, Bournemouth simply couldn't cope with the movement and directness of United's attacking players, who were finding it far too easy to break through the lines.
Diallo's 18th goal contribution of his career (10 goals, eight assists) meant his output had only been bettered by Morgan Rogers (26), Cole Palmer (25) and Joao Pedro (21) for players that are aged 23 and under.
The Cherries' Adam Smith was particularly guilty of giving possession away down the right-hand side in those early stages too, and by the end of the game, he'd lost possession an astonishing 18 times.
Semenyo breaks his goal drought
He wasn't alone in providing such a tardy defensive performance either; his colleagues, Marcos Senesi and Adrian Truffert, also made life difficult for themselves, losing possession on 21 and 19 occasions respectively.
United were well on top and had another four shots at goal before Bournemouth, belatedly, had four of their own in a three-minute period. It was the first attacking foray for the visitors, which didn't arrive until the half-hour mark.
Though the hosts continued to dominate, Luke Shaw's inability to keep hold of the ball allowed Smith to feed Semenyo, and the forward turned on the afterburners to outpace the United defence and fire low across Senne Lammens for a scarcely deserved equaliser.
A first goal in seven games for the striker was also his third against United, but parity was restored during injury time as Casemiro scored from United's 17th attempt of the game, assisted by Bruno Fernandes.
Evanilson draws the Cherries level
The Portuguese's intensity in possession and accuracy in the pass were a joy to watch at times, and the vast majority of his 45 passes in the game were forward.
No sooner had the second half started, however, than Bournemouth were level, Evanilson ending his goal drought within the opening minute.
Marcus Tavernier, who had assisted Evanilson, then scored himself just a few minutes later to silence the Theatre of Dreams. In so doing, Bournemouth had become the first side to score 3+ goals in three successive top-flight games at Man United.
That sparked a home onslaught that was merciless at times, with Diallo and Matheus Cunha having 10 and nine touches in the Bournemouth box respectively.
United's late onslaught
The Cherries were like statues as United's players passed the ball around them with ease, having 77% of the ball in the 15 minutes directly after the hour mark.
With 15 to play, Bruno got the goal his performance deserved, an astonishing free-kick going in off the woodwork for his fourth in eight games against Bournemouth.
Cunha looked to have won it two minutes later, but United's defence was again to blame as Junior Kroupi levelled with seven to play; neither Lisandro Martinez, Heaven, Shaw, nor Dalot getting in a tackle.
The England international aside, the remaining three made only two tackles between them in the entire game - three if you count Yoro's contribution.
United even allowed Bournemouth to have three more shots on target before the final whistle, forcing Lammens into five saves in the match for the first time since he faced Liverpool earlier in the campaign.
An entertaining 4-4 draw the game may have ended up being, but the result won't have suited either manager. It raises plenty more questions about United's back line - and Amorim's insistence on chopping and changing it - than it answers.
Catch up on the match with Flashscore.
