United's spluttering opening to the new season caught up with them at Old Trafford on Saturday.
For the fifth time in six Premier League outings, they fell behind.
But, against a speedy and durable Tottenham team, Ferguson's team left themselves too much to do and slipped to their second defeat of the campaign.
While praising United's second-half performance, Ferguson was furious with what went on before the break.
It followed on from similar lacklustre displays earlier in the season, particularly at Southampton and Liverpool.
And, speaking ahead of Tuesday night's Champions League clash with CFR Cluj in Romania, Ferguson has vowed it will not continue.
"We were well off the pace of the game. I don't think we won a tackle in the first half," said the United boss.
"The second half was probably our best performance of the season.
"When you consider the first half against Southampton, the first half Liverpool and first half on Saturday, we have some work to do.
"You have to be concerned losing goals the way we did.
"It's not planned but I think it will be the last."
Previews of other Champions League Tuesday fixtures
On Saturday, stand-in skipper Patrice Evra said he believed the problem might be mental.
His manager does not think so. Instead, with so many key defenders injured, including Nemanja Vidic, Ferguson is hoping the consistency of Rio Ferdinand's central defensive partnership with Jonny Evans will start to have a positive impact.
"After the first half on Saturday I had plenty of concerns," he said.
"I hope it's an awareness thing because we faced this situation at the end of October last season, and from then on when Jonny and Rio played together consistently we played better."
The observation was acknowledged as being correct by Evans, who has shrugged off the dead leg he picked up at the end of Saturday's game.
"Every defender will tell you that when you have a settled partner you get a good understanding, and with a run of games your match fitness and concentration go up," said the Northern Ireland international.
Ferguson will expect to see signs on Tuesday night as a meeting with the Romanian champions is evidently not going to be quite as straightforward as many imagined when the draw was made.
Back-to-back victories over another Romanian side, Otelul Galati, were the highlight of last season's dismal Champions League campaign.
In contrast, Cluj have started in superb form, registering a superb 2-0 win in Braga a fortnight ago, leaving them, like United, a victory away from taking a firm grip on Group H.
"I don't think you can go away in the Champions League and get lucky if you score two goals and keep a clean sheet," said Evans.
While it is anticipated United's abysmal European form from 12 months ago will prove to be a temporary phenomenon, Ferguson has taken one significant step.
Instead of flying out on the morning before an away game and training in the stadium, as allowed by UEFA, United remained at their Carrington base for their final session in a stated attempt to limit the chances of their plans leaking out.
"We made the decision last season," said Ferguson.
"Most of the time when you go abroad and train on their pitch you can't do anything because everyone is watching.
"By training at our ground we could do what we wanted in terms of picking the team and anything tactical. It was much better."
The absence of Michael Carrick had already been confirmed before departure.
Like Carrick, Ryan Giggs also remained at home due to a virus, while 37-year-old Paul Scholes was rested having completed the full 90 minutes against Tottenham.
It means Darren Fletcher and Tom Cleverley will compete for midfield slots along with Anderson, whom Ferguson concedes was unfortunate to be overlooked at the weekend.
"Anderson has done nothing wrong," said Ferguson.
"His pre-season form was terrific and he's a top player, but I still think that (Paul) Scholes is a great player."
Ferguson was not entirely happy on Monday evening, angrily dismissing a question about the Ryder Cup triumph 24 hours earlier.
Yet, at 70, there is still no thought of it all getting too much, a question posed by a Romanian journalist that drew a wry smile and a well-worn response.
"No," he said. "I haven't thought about that."