Liverpool keeper Alisson was sent off for a blatant handball outside his penalty area as the Reds moved 11 points clear at the top of the Premier League with victory over Brighton.
Jurgen Klopp’s side were coasting to victory after two Virgil van Dijk headers from Trent Alexander-Arnold assists in the space of six first-half minutes.
But Alisson’s red card – for handling as Brighton substitute Leandro Trossard bore down on goal – gifted the visitors a lifeline.
Substitute Adrian’s first touch was to gather the ball out of his own net after Lewis Dunk’s cute free-kick left the keeper – who was still organising his wall – stranded, before Liverpool’s stopper saved late on from Aaron Mooy.
Earlier in the day, defending champions Manchester City were held to a 2-2 draw at Newcastle United.
Leicester City will cut Liverpool’s lead to eight points if they beat Everton on Sunday (16:30 GMT).
Victory means Liverpool have equalled their longest ever unbeaten run in the top flight, having also gone 31 games without defeat between May 1987 and March 1988.
Yet this was anything but straightforward for the leaders as Alisson became the first Reds keeper to be sent off in a Premier League game since fellow Brazilian Doni in 2012.
With his side 2-0 up and closing in on three points, Alisson came rushing out of his penalty area to handle the ball as Brighton attacked.
As a result, Alisson will now miss the Merseyside derby with Everton at Anfield on Wednesday.
His actions set up a nerve-wracking finale and Dunk’s free-kick – an awful goal to concede from Liverpool’s point of view – means Klopp’s side are still without a clean sheet since 28 September.
Adrian saved his side by keeping out Mooy as mid-table Brighton piled forward in search of an equaliser.
The Reds had looked like coasting to victory after Van Dijk’s double, and Brighton keeper Mat Ryan made three fine saves to frustrate Roberto Firmino, twice, and Mohamed Salah.
Liverpool head into a demanding December, a month during which the club will play nine fixtures in four different competitions, with a fifth successive league win – but this was far too close for comfort.
Brighton slipped to 15th in the table after a third straight defeat, but there are grounds for optimism before a busy December programme.
In a week during which Seagulls boss Graham Potter extended his contract to 2025, his side gave the leaders a real scare even before the hosts were reduced to 10 men.
Dunk went close from a Pascal Gross corner before scoring his second goal in as many games, while teenage forward Aaron Connolly also showed flashes of real promise.
With his side trailing 2-0, the 19-year-old managed to create space for himself inside Liverpool’s penalty area and test Alisson despite close attention from Dejan Lovren and Van Dijk.
One worry for Brighton is their defending from set-pieces as Van Dijk was allowed to dominate the aerial duels. That will be a real concern for Potter with matches against Arsenal, Tottenham and Chelsea on the horizon.