Hughes' position has been under threat since Wednesday's abject performance at Tottenham and not even today's 4-3 win over Sunderland looks set to save him.
Roque Santa Cruz scored twice for the hosts, with Carlos Tevez and Craig Bellamy also on target.
Off to a flyer: Roque Santa Cruz's strike (above) was soon followed by Carlos Tevez's penalty
At least his players gave the Welshman a fitting send off. Hughes' men were forced to take the lead three times before finally securing only their second win in 11 games.
Roque Santa Cruz - a man Hughes fought so hard to get from former club Blackburn - scored at the beginning and end of an extraordinary afternoon, which unconfirmed rumours suggested Mancini was present to watch and meet chairman Khaldoon al-Mubarak, who is set deliver his own verdict on an overall transfer outlay in excess of £200million.
Marked man: Manchester City manager Mark Hughes can see his reign unravelling in front of his eyes
Carlos Tevez and Craig Bellamy also found the net to leave Sunderland empty handed, even though goals from John Mensah and Jordan Henderson had pulled them level from two adrift and Kenwyne Jones had nodded home another equaliser after half-time.
For City's ambitious owners, the opening 45 minutes neatly encapsulated the best and worst of Hughes' time in charge.
Having taken the bold decision to axe underperforming £67.5million pair Robinho and Emmanuel Adebayor, Hughes watched with pride as his team ripped the Black Cats apart.
The third minute opener was a dream. From Tevez's precise pass and Bellamy's neat square ball to Santa Cruz's tap-in. As the latter duo had replaced Robinho and Adebayor it must have given Hughes a particular sense of satisfaction.
City soon had another too. Bellamy again causing problems as he was bundled over by Nyron Nosworthy. Tevez drilled home the spot-kick, confirming a massive tick for attack.
Yet it has been apparent for quite some time that City's problems are at the back.
There was a partial excuse for Sunderland's first given Micah Richards had just gone down with an injury that ultimately hastened his exit.
Walking in the air: Kolo Toure and Lee Cattermole collide
Yet that did not excuse Toure's complete failure to pick up John Mensah, who climbed unmarked to steer home Andy Reid's curling right-wing cross from six yards.
It was far too easy for a side aiming to force their way into the top four.
Worse was to follow as Jordan Henderson caused the Blues difficulties they could not deal with.
That Hughes was sufficiently confident about Toure's abilities to make him captain above Gareth Barry only made matters worse as the Ivorian failed to make any contact with an attempted clearance of Mensah's prodded ball across the box.
Henderson crashed home the shot, effectively scrawling a great big cross next to City's defence. Up above, Khaldoon must have been pondering all this.
Yet, with the rumours about Mancini so strong it seems the decision has already been made.
That would be harsh on Hughes on a day when Liverpool's problems appear to be far worse.
However, this is a harsh world, even if the hosts were ahead again at the break thanks to Bellamy.
Ding dong: Craig Bellamy scores City's third goal
One of the undoubted success stories of the Hughes' regime, the Welshman supplied a brilliant curling finish to the far corner when Santa Cruz - making only his second start following his summer arrival from Blackburn - allowed Shaun Wright-Phillips' low cross to roll across the box.
That City were not able to build on their advantage was no fault of Bellamy's.
The Welsh firebrand has reserved the best football of his career for Hughes' management, with City and Blackburn, and will be among those genuinely saddened if what appears inevitable does come to pass.
It was inevitable Sunderland would equalise given what City's season has become.
Henderson was left to cut through three City defenders without any of them following his run. He collected Nosworthy's short pass in open space inside the box and crossed for Kenwyne Jones, who got ahead of Vincent Kompany at the near post to head home.
Kevin Keegan was the manager who vowed to change City, then gave up, claiming there was something unusual in the club's DNA.
So it was totally in keeping what that mad stereotype that Santa Cruz knocked home a fourth after Barry had sent Zabaleta's angled cross bouncing into the six-yard area.
Sunderland defender Michael Turner was sent off in stoppage-time for catching Barry with a stray elbow. But the real story was being written high above the action in the City boardroom.
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