Cardiff City were left reeling as the Seagulls stunned the top-of-the-table side in their own backyard.
Andrea Orlandi’s first-half strike and Leonardo Ulloa’s injury time tap-in was enough to seal Albion back-to-back victories at the Cardiff City Stadium, as Gus Poyet’s side scored a massive away victory and a crucial three points in their pursuit of the play-offs.
Although long periods were spent defending, Albion turned in the sort of gritty, determined and clinical away performance that was lacking at times in last season’s campaign.
Albion had the initial opening when Wayne Bridge’s cross found Ulloa but the Argentinean mistimed his effort and the chance went begging.
Cardiff then began asserting themselves, and Peter Whittingham and his cultured left foot threatened to put the Bluebirds ahead but his curling effort was well pushed away by Tomasz Kuszczak.
And Albion’s Polish international keeper was called into action from the resulting corner as Craig Bellamy’s drive was directed onto the bar.
Despite the hosts' dominance it was Poyet’s side who came closest next; Matthew Upson’s clever chest down into the path of Ulloa was fired towards goal by the striker, only for David Marshall to magnificently push the ball wide.
Albion were once again indebted to their keeper, and nobody more than Dean Hammond. The midfielder’s weak back pass gifted Bellamy a one-on-one and the Welsh international tried to round the Seagulls stopper only to be denied by the sprawling Pole.
Cardiff had not lost their opportunity yet though as the loose ball rolled out invitingly for Bellamy to try his luck once more only for a brilliant reaction save to deny the former Liverpool striker once more.
Cardiff had the better of the opening 45 minutes but were once again denied by some steely and determined defending by Albion’s resolute back four, with both Adam El-Abd
and Liam Bridcutt throwing their bodies in-front of strikes from Aaron Gunnarsson and former Seagull Craig Noone.
Albion had defended excellently and looked dangerous on the break, and Poyet’s side proved how dangerous they could be on the stroke of half-time as they took the lead.
David Lopez’s pin-point cross was expertly turned in first time by Orlandi for his fifth Albion goal and fourth strike since the turn of the year.
Gunnarrsson was unable to capitalise on a lucky ricochet just before the hour mark as he blazed over, as the Seagulls started the second half containing the league leaders.
But on the stroke of 60 minutes the Cardiff faithful were up in arms as referee Kevin Stroud gave a free-kick right on the edge of the area for a foul on Bellamy. The majority of the Welsh crowd were convinced contact from El-Abd was inside the box.
Frazier Campbell may well feel he should have done better as he mistimed a header from Bellamy’s cross before an inspired Kuszczak once again pulled off a blinding save to tip Conway’s dipping strike over the bar; a stop reminiscent of his marvellous save against Hull City at the Amex ten days ago.
The Bluebirds rattled the woodwork once more but in a less conventional way this time, as Conway’s wayward cross inadvertently bounced off the Albion crossbar.
One of the best opportunities of the second half then fell to Campbell who skied his first time effort from Matt Connoly’s cross over the bar.
Midfielder Gunnarsson had been launching long throw-ins into Albion’s box all game and almost caused enough chaos in the area with another trademark long throw on 77 minutes. However the ball deflected off numerous Albion defenders and dropped agonisingly wide for the hosts.
Gunnarsson then turned to his feet in search of an equaliser and his stinging drive pulled yet another good stop out of Kuszczak.
As the clock hit 90 minutes Bellamy snatched first time at a great chance, dragging his effort wide before an excellent counter-attack from Albion almost killed the game.
Gary Dicker's inch perfect pass unleashed Will Buckley but the winger found Marshall equal to his near post effort.
There was to be late drama though as David Lopez broke down the right and picked out Ulloa in the City box, and the striker saw his deflected effort bounce up into the net to secure the three points.