An injury-time goal from Brighton forward Kaoru Mitoma ended Liverpool's campaign in this season's FA Cup as they were beaten 2-1 away to the south-coast
The winger scored after a magnificent control to take Brighton into the last 16 and leave Liverpool's season hanging by a thread.
Although Liverpool improved from their 3-0 defeat in the same ground just 15 days ago and even took the lead through Harvey Elliot's 30th-minute goal, Brighton were level just nine minutes later when Lewis Dunk deflected a shot into the Liverpool goal.
Brighton had more of the ball and more efforts on target than Liverpool, and deserved to win, while Liverpool's UEFA Champions League tie against Real Madrid now takes on an even greater significance.
In the day's most romantic Cup tie, fifth-tier outfit Wrexham drew 3-3 with Championship promotion chasers Sheffield United.
The visitors were reduced to 10 men 13 minutes from time when Daniel Jebbison was sent off, but they netted a 95th-minute equalizer through John Egan after it looked as if Paul Mullin's 86th-minute goal would put Wrexham through.
On Saturday, Kelechi Iheanacho's 68th-minute goal saw Leicester City into the fifth round, although Brendan Rodgers' side failed to impress against a rival from the fourth tier, League Two.
Leeds United were more convincing as goals from Jack Harrison, Junior Firpo and Luis Sinisterra put them on their way to a 3-1 win away to Accrington Stanley from League One.
Two goals from left back Romain Perraud helped Premier League bottom side Southampton beat Championship strugglers Blackpool 2-1.
Fulham were held to a 1-1 draw at home to Championship outfit Sunderland, with the visitors taking the lead thanks to Jack Clarke before a goal from veteran midfielder Tom Cairney earned Fulham a replay.
Son Heung-min scored twice as Tottenham eased past Preston 3-0 in what could have been a difficult visit to the northwest for Antonio Conte's side.
Two goals from Brazilian midfielder Casemiro and another from his international teammate Fred saw Manchester United ease past Reading 3-1 in a match which saw former United legend Paul Ince return as coach of their rivals.
On Friday night, Nathan Ake's goal saw Manchester City beat Premier League leaders Arsenal 1-0, as both teams made several changes to their usual starting elevens
