Arsenal revelled in a scene of high anticipation when they walked out to face Aston Villa but were left looking at a sea of empty red seats 90 minutes later as the Premier League title race took a potentially pivotal twist.
Liverpool stumbled first in a shock home defeat by Crystal Palace before Arsenal's supporters, well at least those of them left, departed Emirates Stadium as stunned as their Anfield counterparts after Mikel Arteta's side slumped to a 2-0 loss.
The title pursuit is nowhere near over with only two points separating the top three, but there is an ominously familiar feel to Manchester City's presence at the top of the table when the pressure valve is tightened.
What will be so frustrating for Arsenal and Liverpool is they were both architects of their own downfalls with desperately poor performances just when they needed victory most.
When the heat was on they were both found wanting.
The big question now is can Arsenal and Liverpool hit back from such savage blows or has the title momentum shifted decisively in Manchester City's favour?
It was all so different before Sunday's late kick-off, with the Gunners having been handed a huge opportunity to re-assert their authority at the top.
Arsenal's supporters trooped in to the Emirates buoyed by the favour Palace had bestowed on them by completing a dismal week for Liverpool after the draw at Manchester United and heavy Europa League quarter-final beating by Atalanta at Anfield.
Liverpool looked leggy and stripped of their usual intensity in the 1-0 defeat by Palace, showing all the signs of running out of gas after energy expended in a chase - for a time at least - of four trophies.
Liverpool defender Andy Robertson said the club's players will "keep fighting" after the shock home defeat by Crystal Palace
However, the hope engendered by Liverpool's loss actually seemed counter-productive for Arsenal, with nerves sweeping around the Emirates in double-quick time when an early breakthrough did not materialise.
The noise at times smacked of desperation, of fear that old failings might come back for a side who were chased down so ruthlessly by City last season.
They did.
City are the experts at applying pressure, as we have seen in previous campaigns, but even they could not have expected both their rivals to struggle in home games on the same day.
Pep Guardiola and his City players will have enjoyed the ideal Sunday as they sat back with their feet up - having a day earlier - before watching Arsenal and Liverpool implode on their own turf.
Liverpool finally paid the price for standing on the precipice too often this season.
Eberechi Eze's goal was the 14th time they have conceded first in the Premier League this season, including four occasions in their past five league matches at home.
They were pushing their luck to think they could come back every time. Eventually they would not get away with it and this proved to be the day.
It means the Kop's dream of a title-winning farewell for Jurgen Klopp has receded - although there is still time for another twist in the tale - in what has been a dreadful week for Liverpool.
The added worry for Klopp is a team counting potency among its greatest threats has suddenly looked blunt at the worst possible time, with just two goals scored in their past three matches.
Can Klopp galvanise and inspire one last time for a glorious flourish? It is a mighty challenge in his final days at Anfield.
Arsenal boss Mikel Arteta was previously Pep Guardiola's assistant at Manchester City
Arsenal's performance carried all the hallmarks of a team weighed down by the pressure on them to deliver, as they fell to their first league defeat since being beaten 2-1 by Fulham on New Year's Eve.
The usual sharpness was lacking and defensive vulnerability displayed in the Champions League quarter-final against Bayern Munich was on show again - with Gabriel particularly uncertain.
It is a long time since the Gunners showed nerves such as this and looked so shaky for so long. The only surprise was it took Villa until the last 10 minutes of normal time to score the goals their play deserved.
Was it nerves? Was it pressure? It certainly looked like it.
Villa manager Unai Emery fashioned a victory that will be sweet after he was sacked by Arsenal in November 2019, only 18 months into his reign.
The wider significance for him is this result increases Villa's chances of finishing in the top four and securing Champions League football next season. Emery has done an outstanding job.
When Ollie Watkins added a second to Leon Bailey's opener, all hope was lost among Arsenal's supporters, with thousands heading for the exits and clearly having no belief in a comeback.
Arsenal's players looked leggy and jaded for most of the second half and exhausted by the end.
Arteta talked up a passable first-half display beyond what it actually was - decent but nowhere near as good as he claimed - but there are no arguments about the second period.
The Gunners looked tight and tense as they saw their hopes of victory edging away and were unable to secure even the consolation of a point as Villa, led by the superb John McGinn and Diego Carlos, deservedly claimed all three.
Will we look back on this as the day when the Premier League title tide turned? The moment when City's relentlessness finally took its toll on Arsenal and Liverpool?
Time will tell but Arsenal and Liverpool will have to find fresh energy and perform several levels above this if the Premier League season, so tight for so long, is not to come to a familiar conclusion.