United have themselves to blame
Of all the frustration Manchester United felt at St. James' Park, the biggest is that the first goal they did eventually concede was all their own doing.
David de Gea took a short goal-kick that was a totally needless risk, and Raphael Varane was forced to concede possession with a wild clearance into the crowd.
Newcastle sensed blood, and Alexandar Isak whipped up the home crowd into a frenzy. Moments later, United failed to clear the ball from the edge of their own box, and the home side would take the lead after overpowering them in the box.
Ten Hag has instilled a never-surrender mentality at United, but this was an afternoon in which their entire approach seemed to be to try and delay the inevitable.
Read next: How the United players rated vs Newcastle
A wasted opportunity
Allan Saint-Maximin was likely licking his lips at the look of the United line up when it emerged there was going to be a change at right-back.
Aaron Wan-Bissaka had travelled up for the match but withdrew due to illness, meaning that Diogo Dalot came back into the side having recently lost his place.
Saint-Maximin had got the better of Dalot in the Carabao Cup final two months ago, but was silenced in the second-half when Wan-Bissaka came on.
The Portuguese needed a big performance on Sunday to not only win the game but win back his position in the starting line up too.
He was by no means the only underperformer in red, but his poor performance highlighted the lack of fight from Ten Hag's side on such an important day.
Tactical risk backfired
Ten Hag labeled Newcastle as 'annoying' in the build-up to their Carabao Cup final clash two months prior, but this was a case of role reversal as United looked to play them at their own game.
Right from the off, David de Gea deliberated over his goal-kicks, and United looked to purposefully frustrate the home crowd by eating up as much time as they could over set-pieces.
It wasn't a pretty approach, though it was deemed a necessary one, as United accepted that they couldn't control the match themselves and would have to resort to such tactics.
The problem with such a game plan was that it would also rely on a moment of magic or a set-piece to have any hopes of winning the game themselves, and that never looked remotely possible.
As soon as Newcastle took the lead, defeat felt inevitable. It proved to be so as well. They tried to play them at their own game and lost.
Failing to cope without Casemiro
Casemiro is not only United's most influential midfielder, but he is also the only one who is suited to the defensive role in a midfield three. His absence was felt again at Newcastle, as was that of the injured Christian Eriksen.
They encapsulate everything that Ten Hag wants from his side, and without them available, it is rather pointless to try and imitate the controlling style of play that he wants.
It was always going to be the case that someone would have to be repurposed into the deeper role as Casemiro served the second of his four-match domestic ban, with Marcel Sabitzer this time tasked to play at the base.
The Austrian has already expressed his preference to play with attacking freedom, and it was once again clear that he is an awkward fit for the role.
United's issue is that there is seemingly no quick fix at the club. They have tried different combinations to no avail and appear no closer to a solution.
Yet, with Casemiro set to miss the next two matches, they will need to try to find one again.
Top four hopes dented
It has felt for a while like United have already sewn up Champions League football for next season, but this is damning evidence that there is still a lot of work to do.
Ten Hag's side are still fighting on three fronts for the remainder of the season, while Newcastle and Tottenham only have to focus on the Premier League for the final few weeks.
It made avoiding defeat on Sunday of the utmost importance to keep their advantage. United could have ended the match in third; they could end the matchweek in fifth.
United will host European football again next season, but it could well be on Thursday nights again.
Next up:
