Jack Ross believes his Sunderland side are still adapting to life in League One but has demanded they learn the harsh lessons quickly.
The 2-1 defeat to Burton Albion ended Sunderland's seven-game unbeaten start to life in the third tier.
It was a sharp wake-up call with the display way below the standards expected by Ross and his coaching staff, though the manager did take ultimate responsibility for the defeat.
Ross named his most attacking side yet with Charlie Wyke - who later went off with a knee injury - Jerome Sinclair, Josh Maja all starting, with support from Lynden Gooch and skipper George Honeyman.
The Black Cats never got going though, struggled to find any rhythm and were unable to mount a successful comeback for the first time this season having again gone behind.
Ross wants his side to show more resilience to the challenges posed by the opposition right from the off and to be more canny when it comes to their physical approach to the game.
"I had no qualms with the scoreline at half-time, they were streets ahead of us in terms of the game," said Ross.
"In terms of how we set the team up, we knew we'd give up certain areas, we asked a lot of Lee [Cattermole] and George [Honeyman] in that respect because they had an extra man in there.
"We looked at our front four and believed they would cause significant troubles but there has to be the fundamentals that underpin it, in terms of how hard you work and how physical you are.
"Physical doesn't mean kicking people, it means using your body. That comes from within. We are still, in my eyes, going through a learning process in this league and what we will face.
"Teams don't come here [to Burton] and win 5-0, away teams may win by the odd goal and be delighted. It is tempering that with where we have been as a club and what has happened recently; I don't want the mentality to drift back to feeling sorry for ourselves and 'here we go again'.
"That has been too readily here in recent times."
With eight games played, the League One campaign remains in its infancy but Ross is demanding his players learn these tough early lessons quickly if they are to achieve their ambitions this season.
Ross said: "If we went and won the game it would have left us in a really good position, that makes it even more frustrating for us.
"We are still in an okay position but do we accept that as being okay? Certainly not from me. That is not why I came to the club. We have to keep growing that in the changing room.
"We have to ensure that when we have days like Saturday that we don't buckle under that, we have shown resilience in terms of the reaction in previous games but you can't just show that resilience when you really need to - we have to have it from the get go. We need to get better at that."
Brewers boss Nigel Clough, meanwhile, felt his Burton side should have won the game more comfortably.
He said: "It was another good game.
"We've been involved in a few in the last few weeks, and I thought that was up there.
"It was two teams going at it hammer and tongs, not always the best quality at times - but I thought the endeavour and honesty and everything shone out.
"I thought we should've won it more comfortably because of the start to the second half.
"I thought in that five or six minutes just after half-time, we should've scored a goal or two and put the game to bed.
"But unfortunately they then go up the other end, it's one shot from 20-odd yards and it's in the top corner and it's a different game then.
"If we'd have just finished one of those chances at the start of the second half, it would've been more comfortable for us."