Match ends, Brighton and Hove Albion 1, Birmingham City 0.
Brighton moved into a play-off position after midfielder David Lopez's second goal of the season ended Birmingham's 10-match unbeaten run.
Lopez struck after the interval, the 31-year-old Spaniard finding the bottom corner of the net after Andrew Crofts had seen his shot parried.
Birmingham had their chances, Chris Burke firing over before Kazenga LuaLua and Burke were both denied.
But Brighton deserved their win, with Crofts and Lopez both going close.
The Seagulls have lost only one of the last seven outings and are now five points behind fourth-placed Derby.
Birmingham, who failed to score for the third time in five games, are 17th in the Championship table, eight points above the relegation zone.
Blues boss Lee Clark can have few complaints, with the hosts managing 24 shots compared to seven by the visitors.
Lopez struck just before the hour mark, the former Athletic Bilbao man pouncing after Crofts forced Darren Randolph to parry his shot.
Striker Jonathan Obika, signed on a 93-day loan from Tottenham, came on for his Seagulls debut with 25 minutes remaining
And the 23-year-old helped set up a chance for Lopez to double the lead but this time he could not find the net.
Birmingham rallied, former Manchester United goalkeeper Tomasz Kuszczak denying Burke an equaliser with a late save.
Brighton manager Oscar Garcia: "Yes, we are sixth, but I am pleased because we won the match and once again the performance of the team was very good.
"That is all, I don't want to comment further about our position in the league.
"I asked the players to be patient. We had to show Birmingham some credit as they were unbeaten in their last ten matches."
Birmingham manager Lee Clark: "We were a bit frustrated with our work in the final third.
"The quality of our final pass was not up to the required standard.
"We weren't clinical enough but the players have shown me terrific character."
- 4AndrewsBooked at 76mins
- 8CroftsSubstituted forOrlandiat 82'minutesBooked at 90mins
- 38InceBooked at 78mins
- 19UlloaSubstituted forObikaat 63'minutes
- 21López MorenoSubstituted forEl-Abdat 90+1'minutes
- 25Lua Lua
- 31CaddisBooked at 56mins
- 17ReillyBooked at 27minsSubstituted forFergusonat 82'minutes
- 8MullinsBooked at 90mins
- 20LeeBooked at 71mins
- 15ElliottSubstituted forBrownat 63'minutes
- Roger East
- Shots on Target
Second Half ends, Brighton and Hove Albion 1, Birmingham City 0.
Andrea Orlandi (Brighton and Hove Albion) is shown the yellow card.
Foul by Kazenga Lua Lua (Brighton and Hove Albion).
Reece Brown (Birmingham City) wins a free kick in the attacking half.
Hayden Mullins (Birmingham City) is shown the yellow card for a bad foul.
Kazenga Lua Lua (Brighton and Hove Albion) wins a free kick on the left wing.
Foul by Hayden Mullins (Birmingham City).
Substitution, Brighton and Hove Albion. Adam El-Abd replaces David López.
Corner, Birmingham City. Conceded by Tomasz Kuszczak.
Attempt saved. Chris Burke (Birmingham City) right footed shot from a difficult angle on the right is saved in the bottom left corner. Assisted by Paul Caddis.
Offside, Brighton and Hove Albion. Andrea Orlandi tries a through ball, but Jonathan Obika is caught offside.
Foul by Jonathan Obika (Brighton and Hove Albion).
Mitch Hancox (Birmingham City) wins a free kick in the defensive half.
Delay over. They are ready to continue.
Substitution, Brighton and Hove Albion. Andrea Orlandi replaces Andrew Crofts because of an injury.
Substitution, Birmingham City. Shane Ferguson replaces Callum Reilly.
Delay in match Andrew Crofts (Brighton and Hove Albion) because of an injury.
Rohan Ince (Brighton and Hove Albion) is shown the yellow card for a bad foul.
Foul by Rohan Ince (Brighton and Hove Albion).