Spurs' difficult campaign has threatened to spiral out of control after a terrible 72 hours where they were knocked out of the Carabao Cup and FA Cup.
Tottenham were without 11 players for the weekend loss at Aston Villa and while Postecoglou launched a passionate defence of his depleted squad, the 2-1 defeat made it 10 losses from their last 20 matches in all competitions.
There are plenty of mitigating circumstances for the Australian, with October 30 the last time key trio Guglielmo Vicario, Micky van de Ven and Cristian Romero played together, while more recently James Maddison, Brennan Johnson and Dominic Solanke have been sidelined.
A small core group has struggled to handle the cycle of Thursday-to-Sunday football during the past two months and even though a number of first-teamers will return this week, scrutiny on the 59-year-old seems to be at an all-time high.
"I'm just going to keep on working like I have," Postecoglou responded when asked how he would approach a rare clear week.
"The ones who have been playing, we've got to give them some time off. We've got the early part of the week and we'll give them some time off.
"The boys who are coming back, we'll get the opportunity to give them a whole week of training which is great.
"Come Tuesday we should have three or four who have been missing. We can give them a full week of training instead of a couple of sessions and then throwing them in.
"By the time we get to the back end of the week, we should have something resembling a squad of players to prepare for a big game. That then folds into the following week when again we've got seven days and no midweek game to prepare for the next game.
"So, that gives us a real good opportunity to get some work into the guys who have been out for quite a while and give some rest to the guys who have been going at it, so by the time we get back to being in Europe and having midweek games, we'll be in a much better shape."
This is not the first time Postecoglou has felt on the brink with similar discourse after Premier League defeats by Everton and Leicester last month.
Spurs are currently 14th before Sunday's clash with United, who have also struggled and perhaps provide a note of caution that a mid-season managerial change does not instantly translate into better results.
What Postecoglou can cling onto is a Europa League last-16 tie pencilled in for early March, but Tottenham must improve their domestic form before focus can turn back to their last hope of silverware this season.
Transfer deadline-day signing Mathys Tel, one of four teenagers to start at Villa, promised improvements.
"Honestly we are sad about the result, but I know the quality of my team-mates, the staff so I believe in the team," Tel said.
"I am not scared about the future. We play against Manchester and we're going to do a job. A lot of players talk in the dressing room and we have to be better. We have to do much (more)."
