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 Liverpool’s 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 them 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 a bout of illness but, in his absence, Hwang Hee-chan and Takumi Minamoto pegged their hosts back to 3-2 with goals either side of half-time.
With the Salzburg coach Jesse Marsch sensing blood, he sent on Haaland and the Norwegian scored his 18th goal of the season within four minutes of his introduction.
There was more than a brief moment of panic as manager, players and Liverpool fans must have been questioning how this turnaround could have happened.
When the bewilderment finally began to subside, Salah struck a brilliant winner 20 minutes from time, volleying home Firmino’s knockdown for his 12th goal in 13 Champions League appearances at Anfield.
Mane then missed a near-post header from Alexander-Arnold’s corner which would have made the finish less anxious than it was, but a first win was in the bag.
It was certainly a Jekyll and Hyde performance from Liverpool as when they were good they were very good but when they were bad they were awful.