Academy graduate Jarell Quansah was denied a dream first goal by VAR in the final minute of added time as Liverpool squandered the chance to secure qualification for the Europa League knockout stage with a 3-2 defeat in Toulouse.
The 20-year-old, replacing ill captain Virgil van Dijk in the side, poked home in the seventh additional minute to claim what would have been a barely-deserved point in southern France.
However, VAR alerted referee Georgi Kabakov to a potential handball after the ball bounced up off Alexis Mac Allister’s chest in the build-up and the Georgian official contentiously chalked it off.
Even a draw would have hardly papered over the individual errors and a lack of cohesion throughout a team registering nine changes.
Toulouse, who had won only three matches prior to this game, had been thrashed 5-1 at Anfield a fortnight ago but were an entirely different prospect on home turf, although they benefited from some shambolic defending.
Liverpool still top the group but their advantage has been cut to just two points and although they have the two weakest sides still to play Klopp’s 450th game in charge was not one to remember as they slipped to their first European defeat this season.
The only cause for celebration on the night came a couple of hours before kick-off when news came through from Colombia that Luis Diaz’s father had been released from his 12-day kidnap ordeal.
But even that could not ease the pain of Kostas Tsimikas dawdling in possession for Toulouse’s psychologically important first goal, or how easily the visitors conceded two more in the second half.
It even took an own goal from Cristian Casseres to get them back into the game at 2-1, only for them to concede again less than three minutes later and it was not until the 89th minute that substitute Diogo Jota set up the late drama.
On the back of the Diaz news the game began brightly for Liverpool with Joe Gomez, who has never scored for Liverpool in 188 games, flicking a Cody Gakpo cross onto the bar.
Diaz turned Mikkel Desler inside out twice to win a free-kick before his knockdown of Gomez’s cross saw Mac Allister’s volley deflected over, with goalkeeper Guillaume Restes’ parrying Ben Doak’s shot.
Toulouse gave Liverpool a warning they did not heed when Gabriel Suazo slid in at the far post to deflect Niklas Schmidt’s cross wide.
Seven minutes later Tsimikas was sloppy in possession and robbed by Donnum, who raced into the penalty area to beat Caoimhin Kelleher via a deflection off Quansah’s leg.
Midfielder Wataru Endo, who had already been booked, was lucky to escape with a lunge on Casseres but he was not so fortunate in surviving the half-time cull – and neither was Tsimikas.
Dominik Szoboszlai and Trent Alexander-Arnold were their replacements, with the unfortunate Doak making way for Mohamed Salah.
Toulouse immediately exposed the space behind Alexander-Arnold, as Gomez had switched to left-back, with Suazo breaking forward and cutting inside Quansah before rolling a shot wide of the far post.
Thijs Dallinga did beat Kelleher in the 50th minute but referee Georgi Kabakov brought play back for a foul on Joel Matip on the edge of the penalty area.
However, Dallinga’s movement got the better of Matip eight minutes later when Diaz lost the ball on the left wing, running in behind to collect Suazo’s cross with his first touch and fire past Kelleher with his second.
Liverpool pulled a goal back they barely deserved in fortuitous fashion in the 74th minute when Gomez’s looping header towards the far post was turned into his own net by Casseres.
But that luck was short-lived as almost instantly Frank Magri converted Suazo’s cross.
Although Jota’s weaving run and shot set up Quansah’s moment in the spotlight late on, the technology denied the young centre-back.