Francis Laurent scored a brilliant injury time goal to seal Southend United's first league win on the road at Brighton & Hove Albion.
The super sub was able to get the better of three Brighton defenders to battle his way into the box and drill the ball into the back of the net from an acute angle for a 3-2 victory.
Lee Barnard's eighth goal of the season and a debut strike from Roy Donovan saw Southend twice take the lead during an action packed first half.
And although Brighton fought back on both occasions, the Blues were not to be denied with Laurent scoring his first goal of the season.
Southend had stormed into an eighth minute lead, following excellent build-up down the right-hand side.
A clever back heel from O'Donovan played the ball into the path of Simon Francis, who delivered the perfect cross for Barnard to produce a diving header into the top corner of the net.
The hosts had looked to response, with Nicky Forster turning the ball wide from inside the box and he was soon allowed far too much freedom to get Brighton back on level terms in the 21st minute.
The Southend defence was caught flat footed as Forster was able to run on to a flick-on and with just Steve Mildenhall to beat, he lifted the ball over the top of the goalkeeper.
The action was fast and furious and the Blues soon regained the lead in the 27th minute, with O'Donovan on hand to score on his debut.
Moussa's left wing corner was headed on at the far post by Adam Barrett and as a scramble to clear the ball ensued in the box, O'Donovan arrived to tap the ball in from close range.
Brighton applied the pressure as they looked for a quick response, with Mildenhall pressed into action to tip a Forster header over the top.
From the resultant corner, the hosts then came even closer when Gary Dicker crashed a shot against the outside of the left-hand post.
But six minutes before half time, Forster was again on hand to equalise for Brighton. The striker was able to get the better of Jean-Yves M'Voto inside the penalty area, as he turned the defender and slotted the ball underneath the body of Mildenhall.
Almost immediately M'Voto left the field injured to be replaced by Osei Sankofa. This caused a reshuffle at the back, with Simon Francis moving into the centre of defence and Sankofa switching to right-back.
As we entered into first half injury time, Jean-Francois Christophe missed a great chance to restore the lead when he was found unmarked from Johnny Herd's left wing cross, but he headed over the top from in front of goal.
There was another early change in defence just four minutes into the second half, with George Friend coming on to make his debut and replace Herd at left-back.
Forster came close to scoring his hat trick, as he again had time to line up a shot inside the box, but Mildenhall was equal to his effort to make a vital stop.
Mildenhall saved Tommy Elphick's header from a corner before O'Donovan's control let him down, as he looked to race clean through on goal.
The drama may have been as less end-to-end in the second half, but a snap shot from Liam Dickinson sailed narrowly wide of the left-hand post while at the other end, Alan McCormack caused panic in the area with a low shot which Kuipers was unable to hold on to.
As we looked set to enter into the closing 10 minutes at the Withdean Stadium, Elliot Bennett looked for a winner when he cracked a strike on to the crossbar from 15 yards.
Dean Cox picked up the loose ball from a free kick and rifled a low shot through a crowd of bodies in the box, which sailed just past the right-hand post.
But as we entered into the first minute of injury time, there was to be late excitement.
Laurent ran towards goal down the left and from what seemed an impossible angle inside the box, he arrowed the ball beyond Kuipers.
It was a superb finish to cap Southend's first win away from home in League One to send them up to eighth in the table.
Southend: Mildenhall, Francis, M'Voto (Sankofa 45), Barrett, Herd (Friend 49), Grant, Christophe, McCormack, Moussa, O'Donovan (Laurent 74), Barnard.
Brighton: Kuipers, Elphick, El-Abd, Forster (Hart 84), Dickinson (C Davies 73), Tunnicliffe, Dicker, A Davies (Cox 73), Crofts, Virgo, Bennett.
