Bobby Zamora came off the bench to break City hearts with a decisive late goal in a game the visitors had their chances to win, never mind draw.
It was City who went in front courtesy of Derrick Williams’ finely taken volley in the 17th minute, only for former skipper Sam Baldock to level the match against his old team eight minutes into the second half.
But it was returning Brighton hero Zamora, back at the club where he made his name, who enforced Albion’s stranglehold at the top of the Sky Bet Championship with a clinical finish eight minutes from time.
Steve Cotterill named an unchanged starting line-up following Friday’s first home victory of the season over Nottingham Forest.
The only alteration from the matchday squad saw Liam Moore replace Wes Burns on the bench, taking City to the maximum permitted five loan players even in the absence of Callum Robinson.
Another of the loanees, Nathan Baker, set the tone with a crunching tackle on the halfway line to reinforce the fact that City had not arrived just to make up the numbers.
It was a confident home team who were first to threaten when Williams was outnumbered down the Brighton right, prompting Liam Rosenior to produce an inviting cross that should have been converted by Tomer Hemed.
The Israeli international rose unchallenged at the far post and his intentions were good in heading the ball down and back across the rooted Frank Fielding, only to see it bounce just past the post.
The hosts then failed to make the most of a couple of set-pieces from useful crossing positions before Williams silenced the Amex with his first goal since January.
Jonathan Kodjia, so often a counter-attacking threat on the road, left Gaetan Bong on his backside in reaching the byeline and chipping the ball up to the far post for Williams to meet on the volley from 12 yards.
The cleanliness of the strike belied the Irishman’s status as a centre-back by trade, as his controlled finish stayed low to beat David Stockdale and the sliding defender, whose attempts to clear proved in vein.
Williams was continuing in his new role at left wing-back and enjoying himself, setting his sights five minutes later from twice as far – again connecting sweetly with a low drive that Stockdale needed two attempts to gather.
By the half hour mark City looked comfortable – almost too comfortable when Aden Flint was caught in possession by Solly March, who squared the ball to offer Baldock the sort of chance City fans will recall him converting countless times in red and white.
But Baldock has only scored once for the table toppers so far this season and let the opportunity pass him by with a tame shot too close to Fielding, who was able to make an important yet frankly rather straightforward stop.
Baldock was fancying his chances against Flint, who allowed the striker to nip in front of him to race on to a long ball and go eye to eye with Fielding again, this time lifting the ball over the advancing keeper only for the retreating Luke Ayling to make a vital clearance from his own goal line.
Brighton had certainly taken their time to get going but dominated the last 15 minutes of the first half.
March, an England Under-21 international, came in off the left flank to set up Hemed for another golden chance in added time, but Fielding produced a low one-handed save – his best of the night – to keep his side in front at the interval.
The 621 travelling fans may have feared a long second half ahead, and the Seagulls offered a glimpse of their intent inside the first two minutes when March escaped down the left and crossed for Hemed, whose clever knockdown was hit first time by right-back Bruno but cleared away by Brighton old boy Elliott Bennett.
The equaliser would arrive six minutes later through a predictable source. This time Bruno turned provider, racing beyond Rosenior on the overlap and crossing low for Baldock, whose slightest touch deflected in off Flint for what may have been an own goal.
City had endured some heavy pressure but looked set for a great chance to retake the lead when Luke Freeman cleverly turned inside Uwe Huenemeier and was clearly tripped by the German inside the box.
But as the away fans rose to acclaim the referee’s whistle, Iain Williamson had other ideas in booking Freeman for an alleged dive.
Cotterill made his first change to shore up the right side by introducing Moore for Bennett as Ayling switched to right wing-back to contend with the dangerous March.
But it was an attacking contribution from the substitute that threatened to turn the tide back in City’s favour, clipping the ball up to Aaron Wilbraham. His flick-on was collected by Kodjia, who turned and unleashed a ferocious shot that needed a strong tip over from Stockdale.
It was a chance out of nothing, but what followed was a clean sight of goal as the contest entered its final 20 minutes.
Freeman carried the ball menacingly into the final third and slipped a cute pass down the side of the defence for Kodjia, who had plenty of time to weigh up his options before drilling a low shot against the legs of Stockdale.
It was a breathless finale to a very decent spectacle in which neither team were content to settle for a point, but substitute Zamora would be the hero for the second time in four days.
Having netted a late winner at Leeds United over the weekend, the veteran striker arrived off the bench and struck the killer blow with eight minutes left.
When his initial lay-off was thumped goalwards by Andrew Crofts and blocked by Flint, it was Zamora who reacted quickest to dispatch a fine volley past the already committed Fielding to win the game.
Cotterill threw on Kieran Agard and Simon Cox – the latter making his debut – in a bid to rescue a point, but Kodjia headed the last chance wide on a night in which City performed admirably but ultimately with nothing to show for their efforts.