In what was a rollercoaster ride for Michael Beale and his side at Prenton Park, Liverpool twice had to come from behind to qualify for the last four.
Tom Dallison gave the visitors an early lead, only for Jose Enrique – yes, you read that correctly – to equalise shortly after.
Beale’s men were stunned by two James Tilley goals early in the second half, however, with the 3-1 scoreline putting the Reds on the cusp of elimination from the competition.
The influential Ryan McLaughlin – on as a substitute following injury – pulled a much-needed goal back soon after being introduced, before Jerome Sinclair also outlined his pedigree.
The young striker, who is rumoured to be on the verge of joining Watford in the summer, repeated McLaughlin’s heroics from the bench, making it 3-3 from close range almost immediately after coming on.
Following a breathless 90 minutes, extra time was called for to separate the two sides, and it was the Merseysiders who would prevail.
Sinclair made himself the hero three minutes after the restart, finishing clinically from McLaughlin’s cross to send Liverpool through to the semis.
Both Mclaughlin and Sinclair have been key players for the U21s for a while now, and their second-half cameos proved match-changing for Beale’s side.
Liverpool U21s: Bogdan, Randall, Enrique, Ilori, Maguire, Virtue (McLaughlin 63′), Ojo, Chirivella, Lennon (Sinclair 75′), Brannagan, Kent (Hart 105′)