For the fifth home match in a row, Erik ten Hag turned to his bench at half-time in an attempt to rejuvenate his side. It was the latest admission that he had got his line-up wrong once again.
Casemiro might well have been hooked even if he hadn&apost pulled up with an injury; Diogo Dalot was fortunate to last as long as he did after a disastrous individual display that stood out even amid the horror show from the rest of his teammates.
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The Portuguese right-back jogged back, seemingly unaware of substitute Miguel Almiron&aposs presence, as the Newcastle forward raced through to give his side an early lead in the match.
Dalot, clearly flustered, struggled to compose himself and was caught out again eight minutes later when Eddie Howe&aposs side had more joy down his flank and Lewis Hall volleyed a loose ball into the bottom corner.
Aaron Wan-Bissaka&aposs introduction was inevitable at half-time and Dalot&aposs case was not helped by the immediate lift he brought at right-back, not that he could have been any worse.
Within three minutes of coming on, Wan-Bissaka had already made a handful of promising forward runs, forcing a corner when his brilliant cross for Anthony Martial was tipped wide at the near post.
“Wan-Bissaka has brought a little bit of something down that side,” Gary Neville glowed on commentary as he hailed the triangle he had formed with Hannibal and Antony in the build-up.
The biggest compliment, though, was that following his introduction, Newcastle stopped targeting the right-hand side as an area of vulnerability. A two-goal lead was obviously a factor in why they laid off, but it was also due to the fact they were getting very little joy against the substitute.
Much tougher tests will come, but it has been little surprise that United&aposs performances have been even worse at a time when they have been without their best full-backs in the form of Wan-Bissaka and Luke Shaw.
The defensive duo have been two of United&aposs most consistent performers this calendar year, and when fully fit, they are pretty much untouchable in their respective roles given the lack of worthy competition.
When United traveled to Fulham a year ago this month, Tyrell Malacia was selected at right back with Dalot suspended, such was the irrelevance of Wan-Bissaka at the time.
Now, the dynamic has completely flipped on its head, with the former Crystal Palace defender a certainty to start at Craven Cottage and Dalot&aposs stock as low as it has ever been in a United shirt after another bad individual performance.
What is most alarming, though, is that United have already repeated their mistakes of old when they gave Dalot a new long-term contract back in May in order to protect his long-term value.
It is looking unlikely the 24-year-old will ever reach the world-class standards expected of him, yet United have signed him up on a contract until June 2028, with an option for a further year on top of that.
While that extended deal protected his market value and kept him at the club for the foreseeable future, it also makes him a much harder asset to shift, given he has the best part of five years still remaining.
The extra dimension to United&aposs dilemma is that Wan-Bissaka is out of contract at the end of the season, though the club are likely to activate the one-year extension clause in his current deal and are keen to tie him down to a new contract.
It means United could well have both right-backs signed up for the next half of a decade, while at the same time still needing to sign another player in that position.
United have provisionally targeted four significant signings next summer, one of which would be a full-back, though those plans could be altered if there is indeed a review of the sporting department following investment from Sir Jim Ratcliffe.
Ten Hag is a huge admirer of Bayer Leverkusen right-back Jeremie Frimpong but United abandoned a move for the former City academy player earlier this year due to Wan-Bissakas encouraging form.
The 22-year-old was due to enter the final year of his contract in July, and United are monitoring possible targets whose deal expires in 2025 – but he recently signed an extension until 2028.