They are a clean sheet away from Wembley, with only a Championship club then separating them from a first piece of silverware in six years. There are times when the Liverpool renaissance is dismissed as a Merseyside myth, but Kenny Dalglish's side are tantalisingly close to a tangible achievement.
After Steven Gerrard, the only outfield starter with a Liverpool trophy on his CV, added to his collection of winners against Manchester City, the travelling supporters started singing about their most improbable triumph: Istanbul. And if this rather attritional affair, like most games, had few common denominators with the surreal spectacular by the banks of the Bosphorus, the outcome was savoured noisily nonetheless.
In contrast, City have their eyes on a rather grander prize than the Carling Cup. Yet their winter break from Premier League action has rather damaged their aura of invincibility. The Etihad Stadium is a fortress that has now been stormed in successive games, back-to-back defeats in the space of four days threatening to make their pursuit of the title an all-or-nothing affair.
A second setback lent itself to a damaging conclusion. Perhaps depth is an illusion glimpsed in victory. Common consensus was that City possessed the strongest squad in the country. Yet stripped of three of its four cornerstones - only the excellent Joe Hart remained - they illustrated the importance of the absent David Silva, Yaya Toure and Vincent Kompany. City's wealth means they are afforded little sympathy when Mancini suggests they need more players, but the manager may have a point.
Indeed, if the pre-match question was which suspension would prove most telling, the answer arrived early. Liverpool lacked Luis Suarez but Kompany's deputy, the callow Stefan Savic, conceded a spot kick for an ill-judged lunge at Daniel Agger. Gerrard drilled it past Hart. "It was a penalty," accepted Mancini.
It brought a winner in an initial battle where one side had a numerical advantage: it was Hart versus Liverpool. The goalkeeper had denied Andy Carroll, Gerrard and Stewart Downing in quick succession as the visitors assumed the ascendant from the off. Gerrard was a dominant, controlling presence in the midfield, Dalglish's gameplan providing reminders of the tactical excellence that was apparent in both wins at Stamford Bridge this season.
But Liverpool were at their most adventurous at the start and at their most negative at the finish. "There were two different performances in each halves," Dalglish said. "We battened down the hatches at the end." They concluded with Jamie Carragher as the most defensive of defensive midfielders, shielding a back five. Unorthodox thinking wasn't confined to the away dugout; Gael Clichy found himself an ersatz right wing-back after a rethink. It wasn't the reason City improved after a perplexingly poor first-half performance - "bad", Mancini accepted - but they did.
Sergio Aguero started to offer a spark and tested Pepe Reina with an angled shot. Micah Richards flashed a header that the goalkeeper gathered so swiftly that much of the crowd assumed it had entered the net. And yet pressure did not produce many chances as Liverpool erected a wall in front of the Spaniard's goal.
Walls were on Mancini's mind, too. Angered that an injury-time challenge by Glen Johnson on Joleon Lescott did not produce a free-kick, let alone a red card, he drew comparisons with Kompany's challenge on Nani on Sunday.
"This tackle was worse than Vinnie's," he added. "Everyone can see this. I think the wall is coming down because there are people in every job who don't say I am sorry." It appeared an attack on the officials, albeit with an oblique analogy. Dalglish, perhaps unsurprisingly, did not see the incident and concentrated on the clean sheet.
"Not too many teams have come here and gone away with no goals against them," he added. Indeed Liverpool were the first since Birmingham secured a stalemate in November 2010. Shutouts are becoming a speciality and frugality is offering them a path to Wembley.
The next stop, however, is a belated first appearance on home soil in this season's competition. Anfield has a proud tradition of semi-final second legs where opponents are intimidated into defeat. If it is maintained, Liverpool's long wait is almost over.
MAN OF THE MATCH: Steven Gerrard - An authoritative display from the captain, who pulled the strings in the midfield. Had Yaya Toure been available to oppose him, it would have been some battle.
MANCHESTER CITY VERDICT: Flattering statistics have surrounded them all season, but now less pleasant ones are emerging. City have been beaten in four of their last eight games and have lost two in a row at home for the first time since 2008. While Mancini felt they deserved to get something, they offered too little in attack. Mario Balotelli cut a bad-tempered figure before exiting early with an ankle injury. But, Hart aside, there was one impressive individual. In a game where two captains led by example, Richards made some surging breaks on the right flank. Good as he is going forward, the better option may be to use the England international in the middle of defence instead of Savic.
LIVERPOOL VERDICT: Dominant at the start, determined at the end, they could enjoy the result even if there was the sense that, by going on the defensive, they invited pressure. Jay Spearing suffered a hamstring injury, but Dalglish did not think it was serious. Indirectly, it led to Carragher's unexpected deployment. The veteran's career began in midfield 15 years ago. Now it came full circle.