United have stumbled badly against sides they would expect to beat, losing to Watford, Bournemouth, Newcastle and West Ham, and face a tough battle to qualify for next season's Champions League.
Manchester United's demoralising defeat against Manchester City in their League Cup semi-final laid bare their desperate need for reinforcements if they are to salvage anything from their stuttering season.
United conceded three first-half goals in a match at Old Trafford for the first time since May 1997 on Tuesday in their chastening 3-1 first-leg loss against Pep Guardiola's men.
Bernardo Silva's wonder strike, Riyad Mahrez's cool finish and an own goal from Andreas Pereira put City well on course for a third straight final before Marcus Rashford gave the hosts faint hope for the second leg on January 29.
The defeat was another stark reminder that United are light years behind the standards set by Premier League pacesetters Liverpool and defending champions City.
Manager Ole Gunnar Solskjaer said there would be no easy solutions as United attempt to claw their way back to the top of English football.
"I've said before it is not going to be a quick fix and the two teams you are talking about are probably two of the best teams in the world," he said.
"That's the task we have ahead of us, it's something that we've started. You can see we are still a way off but we've started something that needed doing."
The problem is that the shoots of recovery are hard to decipher, with United short of technical quality and fight against City.
United have had some impressive performances this season -- including a 2-1 victory at City in the league last month, wins against Chelsea and Spurs and a draw at home against Liverpool.
But they have stumbled badly against sides they would expect to beat, losing to Watford, Bournemouth, Newcastle and West Ham, and face a tough battle to qualify for next season's Champions League.
There are problems for Solskjaer to solve all over the pitch.
Rashford's recent form has helped paper over United's lack of depth up front after they opted not to replace Romelu Lukaku, who left for Inter Milan in August.
United's midfield looks desperately short of creativity in the absence of the injured Paul Pogba and with Jesse Lingard struggling to find his best form. Scott McTominay is also currently sidelined with a knee injury, depriving the side of steel.
And despite boosting their defence with the signings of Harry Maguire and Aaron Wan-Bissaka in the summer transfer window at considerable cost, United do not look like a cohesive unit at the back.
Maguire's arrival has not had the same galvanising impact that Virgil van Dijk's signing had at Liverpool, with United recording just three clean sheets in the Premier League this season. Only Norwich and Tottenham have had fewer.
"We are a young team and with the injuries we've had and illness it shows more and that's something we are looking at," he said.
"If there is something there for us I've got the backing to do something but if it is not the right thing we won't do anything."
Aston Villa midfielder Jack Grealish and Leicester midfielder James Maddison, as well as Dortmund's Jadon Sancho, have all seen their names linked with a move to Old Trafford.
The problem is that January is a notoriously difficult time to persuade clubs to part with their best players. Leicester boss Brendan Rodgers has said nobody he wants to keep will be leaving the King Power Stadium this month.
Alongside the constant speculation over Pogba's future, Solskjaer may have another headache, with reports that veteran defender Ashley Young has opened talks over a move to Inter Milan.
"We can't weaken ourselves. We've got to strengthen ourselves if any movement is going to happen," Solskjaer said.