Kaoru Mitoma's extra-time strike helped Brighton advance to the fifth round of the FA Cup, beating defending champions Liverpool.
The two sides appeared poised for a rematch at Anfield towards the end of a game that had previously seen Harvey Elliott's opener quickly undone by Lewis Dunk.
However, Mitoma pulled off a smart finish at the death to give the Seagulls their second win over Jurgen Klopp's side in just two weeks.
It may also have ended any realistic hope of the Reds lifting the trophy this season, just months after they came tantalizingly close to a fourth in a row.
Brighton vs. Liverpool result
LIV — Elliott — 30th min
BRI — Dunk — 39th min
BRI — Mitoma — 92nd min
Influencers can stick to a positive attitude
As that game entered the 90th minute, it looked as though Liverpool were heading towards another respectable result as they continued their quest to turn the season around and boost their attributes with useful confidence.
But while the late winner's goal conceded would change perceptions, Klopp had no choice but to cling to the positives of the bitter defeat.
The biggest advantage is the huge improvement in the Reds' defensive structure compared to the 3-0 defeat (and could have been more) at that stadium two weeks ago.
If Liverpool can continue like this, they will win more games in the future, although that may not mean much in the midst of their most disappointing season.
Bajcetic shows value again
A key reason for the Reds' recent progress, particularly in midfield, has been the emergence of teenager Stefan Bajcetic as a viable option.
The Spaniard impressed again here, snapping tackles and using the ball deftly in tight areas to keep Brighton's pressure at bay.
The value of his contribution was perhaps best highlighted by Fabinho's pathetic exaggeration in his late cameo when he should have been sent off.
There's one reason why Bajcetic is now Klopp's first-choice No. 6: he's a far better option than any of his older peers.
Brighton's dream season continues
While the focus will mostly be on Liverpool as hopes of winning another major trophy evaporate, it is only fair to give Brighton their due.
This game proved that their last victory over the Reds was not a fluke, even if it was not easy for them to beat their opponents in the previous game.
Many will be worried about the Seagulls following Graham Potter's loss to Chelsea, but they do appear to be improving under Roberto Di Derby.
In England, no team is happy with a draw in the next round.
How Brighton vs Liverpool happened, highlights
FULLTIME: Across the Amex and Brighton into the fifth round of the FA Cup at the expense of the defending champions thanks to the drama of the night.
90 minutes (+2): Goal! Mitoma has won the title for Brighton! ! ! !
The hosts sent a free-kick to the far post, Estupinan passed the ball to Mitoma and the Japanese cut inside with a bouncing ball and pushed it high into the top of the net in incredible progress.
VAR was reviewing Estupinan for possible offside but he stopped and so did the goal.
90 minutes: Five minutes of extra time - can the two sides win?
88': David Coote takes no further action, so the yellow card remains the decision, but Ferguson looked miserable as he limped off to be replaced by Udav.
86 mins: Minutes after Bajcetic was substituted, Fabinho Ferguson clumsily grabbed the cleat with what looked to be a rather ferocious-looking rake in an attempt to win the ball, which he might have spotted if VAR had had a look I am in trouble.
83': Alexis Mac Allister goes down and receives medical treatment after being shoved hard by Ibrahima Konate.
No foul, according to the referee, who should have sent the Frenchman off the field as the last man standing.
80th minute: Ferguson shoots from close range in the penalty area, but Konate blocks the ball well.
79th minute: Thiago Alcantara replaces Curtis Jones, Liverpool make their fourth substitution.
77th minute: Alisson rushes off the field after the ball goes up his ass, playing the role of sweeper and goalkeeper. There's plenty of time to push the winners hard on both sides.
71st minute: Great chance for Brighton!
Mitoma used the outside of his boot to select a nice low cross from the left and March seemed destined to head home with a side foot, but Alisson came out quickly and did enough to block the shot.
67': Danny Welbeck makes way for Brighton as De Zerbi tries to turn things around. Billy Gilmore replaced him.
63 mins: After the Dutchman's excellent footwork and acceleration, Dunk now follows Konat's jersey pull at Gakpo.
62 mins: Konate came on late as Ferguson tried to regain possession, a well-deserved warning.
59': Liverpool made three substitutions before the hour, with James Milner, Jordan Henderson and Darwin Nunes replacing Trent Alexander-Arnold, Naby Keita and Xavi Elliott.
55min: Mitoma leaves Alexander-Arnold and pulls back a ball that ends up on March, but he can't control his shot and flies over the bar.
51': Brighton win a free-kick 25 yards from Liverpool's goal, Dunk takes it wide but misses it.
46': Amex start again after Brighton swap Webster for Weltman at half-time.
Intermission: An enjoyable 45 minutes of football is over.
43': Gakpo leaves his midfielder to leave Elliott behind, but the youngster's second touch shows Lamptey has enough of the ball and he makes a good recovery challenge.
39 minutes: Goal! Brighton upgrade!
Liverpool took a corner through Alexander-Arnold but it wasn't until Lamptey fired a powerful low shot into goal that Dunk's easy delivery fooled Alisson and found the goal.