The Red Devils' loss-win pattern in pre-season continued at the Williams-Brice Stadium in South Carolina, where they were condemned to their third defeat from five exhibition matches this summer.
Arne Slot's Liverpool found themselves two goals to the good at half time courtesy of efforts from Fabio Carvalho and Curtis Jones, before Kostas Tsimikas added some gloss to the scoreline just after the hour mark.
The scoreline did not truly reflect the Red Devils' performance, as they fired 18 shots compared to nine for the Merseyside giants, but a lack of ruthlessness let them down severely.
Man United were already without Leny Yoro (foot) and Rasmus Hojlund (hamstring) for the meeting with Slot's team, but they received two boosts before kickoff, as Antony and Marcus Rashford both made the squad after picking up knocks against Real Betis.
Man United hit with defensive blows in Liverpool loss
However, Ten Hag's defence was ravaged on Saturday evening, as Harry Maguire firstly failed to make the matchday squad, while Victor Lindelof and Jonny Evans were both taken off at the half-time break.
Later in the second period, young defender Will Fish was loaded onto a stretcher following a collision with Liverpool starlet Harvey Blair, and Ten Hag took the unusual approach of entering the field to console the 21-year-old.
Ten Hag offered an update on all four players after the contest, confirming that Fish's problem was an impact injury, while Evans felt unwell and Maguire had to miss out as a precaution.
The Dutchman also affirmed that Lindelof's withdrawal was more preventative than anything else, but he was unable to offer any guarantees ahead of next weekend's Community Shield showdown against Manchester City.
"Always, we have to see what has gone on. The assessment, of course, with Will Fish is it's an impact injury. We also had to sub Jonny Evans at half-time because he was ill," Ten Hag told MUTV.
"Victor Lindelof [was] a precaution. So, yeah, there are some injuries, but we have to see how bad it will be. Pre-season is always tough. But, yeah, Harry Maguire, as a precaution, we leave him out. And we had, of course, some injuries, but that is part of club football. We have to develop our team and make some good progression."
In addition to the quartet that Ten Hag mentioned, right-back Aaron Wan-Bissaka failed to complete the full 90 due to an apparent issue, although the Man United boss did not deliver an update on his problem.
What could Man United's defence look like against Man City?
A decimated Man United will be licking their wounds during their flight home, although with Maguire and Lindelof on the "precautionary" list and Evans being ill, there is hope that they will be available for the imminent Wembley trip.
Should the worst come to the worst and all three miss out, Ten Hag should at least have Lisandro Martinez and Luke Shaw back, while Casemiro can also fill in centrally if required.
Man United are attempting to address their defensive issues by signing Bayern Munich duo Matthijs de Ligt and Noussair Mazraoui, but they are supposedly short of the Germans' valuation and have seen one combined bid rejected.