After Jérémy Doku’s second-half substitute appearance transformed Manchester City into a high-octane proposition, the smart money was on the momentum continuing and the penalty shootout going their way.

So it was as Enzo Maresca’s side triumphed 4-3, Gerónimo Rulli’s save from Lewis Dunk’s fifth spot-kick proving decisive, the Argentinean also having repelled Yasin Ayari’s fourth penalty.

While Jason Steele had kept out Mateo Kovacic’s penalty, City progressed after Brighton twice took the lead – via Malick Yalcouyé and Georginio Rutter before being pegged back by Kovacic and Vitor Reis.

This first of a City-Brighton double-header (part two is Saturday’s league fixture at the same venue) featured opponents coming off rare losses. City’s 2-1 defeat at Aston Villa was a first in the Premier League and was matched by Brighton’s 2-0 loss at Liverpool, only their second in the competition.

Maresca called Fabian Hürzeler’s team “fantastic” and he was correct: they are third, only five behind the hosts and league leaders, City, and, as is their way, operated a gameplan of intense press and fast movement into the spaces, popping the ball about.

This too is an approximation of the Maresca blueprint, though seeing Rayan Cherki dip forward past Olivier Boscagli and draw a foul from Michael Svoboda was to witness an X-factor player Brighton do not have in their ranks.

The resulting free-kick led to a corner from the right, then a break down the same flank where Phil Foden’s cross begged to be smashed home but Floyd Samba, Erling Haaland’s stand-in, was not in position.

With five A-listers – Haaland, Rúben Dias, Elliot Anderson, Gianluigi Donnarumma and Josko Gvardiol – on a break, City’s tally of changes was nine, the Seagulls seven. Yet so deep and well drilled are squads in the current era neither City or their visitors were disrupted.

Instead Foden, who is not a regular at the moment, was a picture of fluidity when moving inside from the right wing to lay off the ball and Yalcouyé could precisely time a shoulder barge on Rico Lewis that stole possession in the wide area.

Further quality was on show when Boscagli’s chip took out City’s backline, Ayari flipped the ball across the area and the opener could have been Brighton’s, but Rulli’s clean sheet remained intact.

Then Yalcouyé did breach Rulli – though there was the proverbial hint of offside about the forward as his shot pinged off the goalkeeper and in. With no video assistant referee in the Carabao Cup the goal stood, though it was soon cancelled out by Kovacic. Foden fed him and from the edge of the penalty area he threaded the ball beyond Steele low to the left corner.

For the second half Maresca introduced Rayan Aït-Nouri and Ryan McAidoo for Ayyoub Bouaddi and Samba. Instantly, though, City conceded: Brighton slipped through the lines with ease, and Jaouen Hadjam’s cross was slid in by Rutter. The No 10’s grin went wide in celebration. The Seagulls were heading through, City out. Aït-Nouri, skipping down the left, tried to do something about this, but his ball over was aimless.

At least there was pace in the foray, which those in blue could lack. But also Maresca’s team had become sloppy – a long-range Cherki pass that ended in Steele’s gloves was emblematic.

Boscagli’s corner that dipped viciously close to Rulli’s goalline was far more dangerous, so just after the hour Maresca introduced a first big gun – Jérémy Doku, for Allan – this coming after Rutter ran in and went close to a second, underlining Brighton’s ascendancy.

When Doku played Aït-Nouri in through the left, it was a rare City attack and showed the value of having the Belgian now able to affect the game.

At this point, though, the decision to allow his alpha-quintet the night off was backfiring on Maresca. City lacked control and were toothless. Doku, again, cut through Brighton but there were no runners to prosper from his infield delivery. Hürzeler’s team tried to squeeze time and snaffle the ball whenever City tried to move them about.

This was a first passage in which City camped in Brighton territory. Suddenly those in green were having to answer questions. Foden’s burst that drew a free-kick from Rutter near the 18-yard line presaged one they could not answer. Cherki blasted this, Reis stuck out a boot, Steele was wrongfooted, and it was 2-2. Doku had lit up City, his presence terrorising Brighton’s defence and turning the tie.