Blues fell to a 3-1 defeat at the hands of league leaders Brighton at the Amex Stadium.
Gianfranco Zola's side put in a spirited performance in Sussex but were beaten by goals from Glenn Murray, Tomer Hemed and Uwe Huenemeier. Che Adams pulled a goal-back late on but it was to be a very frustrating night on the whole as Blues left Brighton empty-handed.
Zola freshened his side up for the game, making four changes to the side that drew to Ipswich on Saturday.
Adams and Stephen Gleeson came in for David Davis and Maikel Kieftenbeld, whilst Clayton Donaldson replaced Lukas Jutkiewicz upfront.
The only other change saw Cheick Keita start in place of Paul Robinson, who didn't make the trip to the South Coast.
Blues started with their usual 3-5-2 formation and found themselves matched up against a Brighton side who had made four changes of their own.
Brighton came flying out of the traps, and with less than two minutes on the clock scored the opening goal of the game through striker Murray.
Anthony Knockaert played in Bruno Saltar down the right flank who fizzed a ball into the middle that was met by Murray, the talisman was on hand to poke the ball past the outreached hand of Tomasz Kuszczak to put Brighton 1-0 up.
Blues looked to respond immediately, and within a matter of minutes had a great opportunity to equalise.
Craig Gardner won a free-kick just outside the area after being brought down by Lewis Dunk. The midfield maestro stepped up to take it but saw his effort cannon back off the crossbar and away from danger.
This seemed to galvanise Blues, who despite conceding the early goal, looked to have settled into the game a lot quicker than the hosts.
Blues began to enjoy a sustained period of possession as they searched for a way back into the match.
Blues created a handful of chances, this time Donaldson was the main architect. The Blues frontman made a brilliant diagonal run into the area before unleashing a powerful shot on goal which was blocked by the on-rushing defender Dunk in the 19th minute.
As the game approached the midway point in the first-half it was Adams who was next to try his luck. The Blues starlet using his pace to beat off Dale Stephens, before drilling a volley inches wide of the far-post.
Blues continued to test the Brighton rearguard and although the scoreline didn't reflect their superiority, Zola's men were playing much the better football.
Just past the half-hour mark it was Adams at the heart of things again, as he dribbled past Huenemeier to create an opening on goal, but the referee was quick to put a stoppage to play as the attack-minded player was adjudged to have taken the ball over the line for a goal-kick.
Blues were playing delightful football and as the clock ticked nearer to half-time, they continued to show signs of promise, limiting Brighton to shooting from range. Stephens ignoring the run of Knockaert before blazing the ball into row Z, much to the delight of Kuszczak in the Blues goal.
That was to be the last action of the first-half as the Seagulls went in at the break a goal to the good.
Half time: Brighton and Hove Albion 1 Blues 0
Blues started the second-half as they ended the first, comfortable in possession and the team in the ascendancy in the early exchanges.
But they were hit with a sucker-punch shortly after as Hemed bundled home from close-range to double Brighton's advantage.
Blues were undone in similar fashion to the hosts' opening goal, this time a looping cross from the left found Murray who headed the ball into the path of Hemed, who in turn had the simplest task of chesting the ball home from five-yards out to put Brighton two-up.
Blues searched for a way back into the encounter, Donaldson with a weaving run to the edge of the box before firing his effort wide of David Stockdale in the Seagulls goal in the 51st minute.
Not long after, Blues were stunned as Brighton extended their lead through Huenemeier, his shot from twenty yards out deflected off Donaldson before flying past a helpless Kuszczak. An extremely unfotunate ricochet that on any other day would have ended up high in the stands.
Blues undeservedly found themselves with a mountain to climb, and Zola looked to change things around by bringing on Kerim Frei and Kieftenbeld in place of Gardner and Robert Tesche.
And, it was only a matter of moments before Frei was in the thick of the play, receiving the ball down the channel, before cutting inside and dragging his strike inches wide of the right-hand post.
Just past the hour mark, Blues had strong claims for a penalty as Donaldson went down under the challenge of Gaetan Bong, however the referee waved away appeals much to the frustration of the Blues fans behind the goal.
And that was to prove to be Donaldson's last action of the night, as he was replaced by Jacques Maghoma with twenty minutes remaining.
Blues continued to show grit and determination, and got their just reward with five minutes remaining as Adams slotted home from inside the six-yard area to reduce the deficit to two.
Emilio Nsue worked the ball to Frei, who drived forward before playing in Maghoma, who backheeled the ball to the feet of Adams to pull a goal back for Blues.
This made for an entertaining last few minutes, as Blues continued to pressure the hosts defence and went close therafter through a handful of opportunities.
First, Kieftenbeld connected with a Gleeson cross but was unable to direct his effort goalwards, before the substitute found himself with another chance but fired his volley straight into the arms of Stockdale.
That was to be the last opening of the game as Blues succumbed to a 3-1 defeat down in the South Coast.