The Reds travelled to Old Trafford for the quarter-finals still capable of winning an extraordinary quadruple in Klopp's farewell season, having already hoisted the EFL Cup trophy aloft less than a month ago.
Klopp's crop were on course for another Wembley sojourn midway through the tie, as Alexis Mac Allister and Mohamed Salah's quickfire strikes turned the quarter-final around after Scott McTominay's opener.
The visitors were the dominant force as the clock ticked down in the second half, but they failed to convert their supremacy into goals and were stunned by Antony's 87th-minute equaliser, just the Brazilian's second goal of the season.
The chaos continued in the additional 30 minutes, as Harvey Elliott's long-range effort propelled Liverpool back into the lead, only for Marcus Rashford — who had missed a golden chance at the end of normal time, albeit one that would have been ruled out for offside — to peg the Reds back again.
Penalties were looming at the Theatre of Dreams, but with 120 minutes on the clock, the seldom-seen Amad Diallo managed to pick out the far corner to send the home crowd into raptures, although he was sent off for a second bookable offence after taking his shirt off.
Liverpool did not have sufficient time to make their numerical advantage count, though, as Erik ten Hag's men snatched a semi-final place from the jaws of elimination, and when it rained it poured for the Reds.
Already without eight players due to injury, Klopp revealed to ITV Sport that Luis Diaz, Cody Gakpo and Darwin Nunez had all sustained issues of undetermined
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