Boss Gary Johnson brought on Phil Jevons up front in place of Wayne Andrews with less than half an hour played. The change paid off handsomely as Jevons scored both goals to take his tally for the season to 15.
He made the all important breakthrough two minutes before half-time when the Brighton defence allowed a corner from Brian Wilson to reach him towards the back of the penalty area.
Jevons controlled the ball on his chest before finding the far top corner of the net with a well struck volley. It was a moment of quality out of keeping with a messy match on a muddy pitch which made fluent football almost impossible.
City almost went ahead in the 36th minute when a free-kick by David Noble from an acute angle rebounded off the crossbar.
Nick Ward had Brighton's best effort in the first half as his curling shot from outside the box forced Adriano Basso into a spectacular diving catch.
Brighton pressed and probed in search of an equaliser after the break without causing Basso and his defenders too many alarms.
Brighton captain Dean Hammond rose above his marker to meet a corner at the far post from Kerry Mayo but he could not direct his header on target.
Brighton's hopes of retrieving a draw suffered a blow eight minutes from time when substitute Tommy Fraser received a straight red card from Premiership referee Mike Riley. The young midfielder trod on the back of Basso, an offence interpreted by Riley as violent conduct.
The decision angered the home fans and they were even more agitated two minutes later when Riley awarded City a penalty. It was a straight-forward decision as Hammond hauled down Wilson as he cut in from the right wing.
Jevons made no mistake from the spot as he sent Brighton's on-loan goalkeeper Scott Flinders the wrong way to end the contest.
He made the all important breakthrough two minutes before half-time when the Brighton defence allowed a corner from Brian Wilson to reach him towards the back of the penalty area.
Jevons controlled the ball on his chest before finding the far top corner of the net with a well struck volley. It was a moment of quality out of keeping with a messy match on a muddy pitch which made fluent football almost impossible.
City almost went ahead in the 36th minute when a free-kick by David Noble from an acute angle rebounded off the crossbar.
Nick Ward had Brighton's best effort in the first half as his curling shot from outside the box forced Adriano Basso into a spectacular diving catch.
Brighton pressed and probed in search of an equaliser after the break without causing Basso and his defenders too many alarms.
Brighton captain Dean Hammond rose above his marker to meet a corner at the far post from Kerry Mayo but he could not direct his header on target.
Brighton's hopes of retrieving a draw suffered a blow eight minutes from time when substitute Tommy Fraser received a straight red card from Premiership referee Mike Riley. The young midfielder trod on the back of Basso, an offence interpreted by Riley as violent conduct.
The decision angered the home fans and they were even more agitated two minutes later when Riley awarded City a penalty. It was a straight-forward decision as Hammond hauled down Wilson as he cut in from the right wing.
Jevons made no mistake from the spot as he sent Brighton's on-loan goalkeeper Scott Flinders the wrong way to end the contest.