Anfield was hosting a landmark 100th European Cup match but very few of those occasions would have seen them squander a three-goal lead.
Leading through goals from Sadio Mane, against his former club, a rare but brilliantly worked Andy Robertson goal and Mohamed Salah, the European champions were in cruise control.
It merely seemed a matter of how many more with almost an hour to play but uncharacteristic casualness crept into their play and they almost paid dearly for it.
The last time this ground hosted Champions League football it witnessed one of the competition's greatest comebacks as Barcelona were defeated 4-0 in the semi-final second leg.
Five months on an altogether different turnaround left Jurgen Klopp's side confused and chasing shadows as Salzburg proved there is much more to then than teenage goalscoring sensation Erling Braut Haaland.
The son of former Leeds, Nottingham Forest and Manchester City midfielder Alf-Inge Haaland was only fit enough for a place on the bench after with illness but in his absence Hwang Hee-chan and Takumi Minamoto pegged their hosts back to 3-2.
With Salzburg coach Jesse Marsch sensing blood he sent on Haaland and the Norwegian scored his 18th goal of the season within four minutes.
There was more than a brief moment of panic as manager, players and fans questioned how this could have happened.
However, there was still one more twist to come, with Salah's volley settling things 20 minutes from time.
It was a Jekyll and Hyde performance from Liverpool as when they were good they were very good but when they were bad they were awful.
Their defence, with regular centre-back Joel Matip's replacement Joe Gomez showing obvious signs of ring rust, was breached seemingly at will in the second half.
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