Michael Beale called on his Rangers players to grasp a "big opportunity" at Ibrox in Sunday's first Old Firm clash of the campaign.
Given depleted Celtic were travelling with a makeshift defence, consisting of derby debutants Gustaf Lagerbielke and Liam Scales, Beale's men had the chance to make an early season statement against a Brendan Rodgers side with questions to answer.
Instead, it was Rodgers who batted away any lingering doubts while further pressure will inevitably mount on his Rangers counterpart.
The Ibrox boss can perhaps count himself unlucky with Kemar Roofe's contentious disallowed goal - a "harsh call" in the eyes of Beale - but yet another defensive lapse for Kyogo Furuhashi's winner and a serious lack of cutting edge only increases the Ibrox doubters.
"It's been a rough week," said the Rangers manager, whose side were eliminated from Champions League qualifying with a heavy defeat by PSV Eindhoven on Wednesday.
"It's a desperately disappointing day for everybody. The Celtic goal is an error on our part, a huge error, and we would like to be more inventive and ruthless because the chances were there.
"We're behind them now and we have a lot of catching up to do. We have to come back stronger."
'Rangers haven't improved in attack'
A derby victory in May, albeit when Celtic had already wrapped up the title, had the potential to break down a psychological barrier that has plagued Rangers in this fixture. But the same issues resurfaced.
Beale cannot legislate for a controversial decision going against his team, but he will have to account for his defence switching off again and his fresh frontline failing to make the most of their opportunities.
The Ibrox side had almost three times the amount of touches (34) in the opposing box as Celtic (12) and more than double the number of shots (11 to five) in the penalty area.
With four shots, Kyogo got his goal. With a combined nine efforts from Rangers strikers Danilo and Sam Lammers, they failed to find the net, while fellow new recruit Cyriel Dessers did not manage a single strike in his 76 minutes on the pitch.
Those numbers only add fuel to the concerns about the Beale's summer recruitment, which included no new centre-backs and heavy spending on a new-look attack that is misfiring.
"Danilo was [reportedly] £6m," former Rangers striker Kris Boyd said on Sky Sports. "These are not development players. You're going to be judged in the big games. For the money that's been spent, why didn't they get a Lawrence Shankland?
"Have they improved in that area? Not for me. If you don't get your recruitment spot on, you're going to come under scrutiny. That's where Beale finds himself right now."
Rodgers' players 'stood up' to occasion
"I said to them before the game that I needed men today and the players stood up," Rodgers told BBC Scotland.
Considering nine of his XI were experienced campaigners in this fixture, there can be doubt that comment was directed towards his centre-back pairing.
Both Scales and Lagerbielke - who was deemed to have been fouled in the preamble to the disallowed Roofe goal - endured shaky starts.
However, with a bit of additional help from a wasteful Rangers attack and the experience of Joe Hart between the sticks, both centre-backs delivered a colossal second-half display.
Scales' tally of three interceptions was the highest of any player, as was his 10 clearances, while Lagerbielke, who registered the most touches (91) for Celtic, won five of his seven duels.
"It's a massive result for the squad when you consider virtually half the team is unavailable," Rodgers added. "A lot of the new players needed that big win to feel what the intensity is like at a club like Celtic.
"Second half, we had to show resilience and fight. To come here, keep a clean sheet and win with not one away supporter in the stadium is brilliant."