There has been a growing sense of cautious optimism at Old Trafford in recent weeks after a productive transfer window to date, with new signings Leny Yoro, Joshua Zirkzee, Matthijs de Ligt, and Noussair Mazraoui all paraded on the pitch before kick-off.
However, it felt like this was being held in place like a sticking plaster over a wound, which was almost ripped off, had André Onana not been alert to parry over Kenny Tete's ferocious long-range strike.
Casemiro attempted to take matters into his own hands for the hosts, but blazed his strike over the bar following some promising build-up play involving Mason Mount and Kobbie Mainoo.
The Brazilian then reacted to Bernd Leno’s misplaced short clearance to tee up Bruno Fernandes, but he could only fire the ball straight at the German.
The Casemiro and Fernandes combination almost paid off again in brilliant fashion, but Leno was alert to the latter’s shot, sparking a cry of anguish from the Portuguese midfielder, in arguably their best chance before HT.
Leno was proving to be an excellent last line of defence for the Cottagers, making another fine stop to deny Mount in a move instigated by a sublime long-range pass down the line from Fernandes.
Mainoo then fired wide after some more excellent United build-up play down the left-hand side, giving ten Hag some room for encouragement.
However, familiar defensive vulnerabilities were never far away, as Onana was called into action to parry away a speculative deflected effort from Rodrigo Muniz.
Fulham were gaining plenty of joy on the counter-attack against United’s porous defence, and had it not been for an excellent goal-line clearance by Lisandro Martínez, former player Andreas Pereira would have made the hosts pay for their openness at the back.
It looked like being one of those nights for a Red Devils side also lacking a clinical edge up front, with Tete intercepting Alejandro Garnacho's cross heading towards Marcus Rashford in the box.
Zirkzee entered the fray for his first outing in the famous red shirt just past the hour mark, and produced the game’s telling action in the 87th minute. His superb instinctive prodded finish from Garnacho’s cross was a rare moment of quality in an otherwise inept attacking performance from ten Hag’s men, sealing a hard-fought win.
There would have been an argument for Marco Silva’s side to leave Old Trafford with a share of the spoils, after coming close to securing consecutive away league win over their illustrious opponents for the first time.
Ten Hag’s side had a golden opportunity to add extra gloss to the scoreline, but Garnacho somehow scuffed an absolute sitter with the goal gaping, perhaps summing up how far United have to go in order to be judged as serious title contenders once again.
Flashscore Man of the Match: Noussair Mazraoui (Manchester United)