Two goals by Robbie Fowler and another by Patrik Berger put a gloss on a scoreline that, for much of the evening, looked as though it would signal an embarrassment for Liverpool. They had every reason to expect an easy match after gaining a 2-1 advantage from the away leg; instead Sion were ahead in the tie twice.
"We defended badly," Roy Evans, the Liverpool manager, said, "and in Europe you don't normally get away with it, certainly not at the top end. But we are such a talented bunch when we have to chase things and we got out from behind the eight-ball tonight. You couldn't do that week in, week out."
Evans had asked the team to finish the job quickly last night to ensure they could concentrate on the Premiership until the March quarter-finals, and to an extent his players followed his instructions to the letter. Except, after 22 minutes, his defence had gone so absent without leave that their participation in Europe looked wholly in jeopardy.
The first Sion goal came after 19 minutes when John Scales stretched and missed a ball on the right and Christophe Bonvin used the space so well that Frederic Chassot could tap in his cross from five yards at the far post. Three minutes later it was 2-0, the home team loitering to watch admiringly as Bonvin turned, teed himself up and then beat David James from 25 yards.
The Kop went as quiet as a morgue, scarcely taking in that Liverpool were behind on aggregate, but as the urgency of the situation increased their volume of support, the home team responded with waves of attacks.
Most of them revolved around Steve McManaman, whose quick feet drove the Swiss dizzy all night. As Liverpool fell behind, he was pushed ahead of Berger into a striker's position and the tactical move paid off almost immediately, the England winger scoring from eight yards from Jason McAteer's 28th-minute cross.
The tie was level now and the teams attacked each other with such abandon that it was a minor miracle that no further goals came before the interval. The second half more than made up for it, however.
McManaman, inevitably, was at the fore, and it was his pass after 54 minutes that allowed Stig Inge Bjornebye the chance to charge at the Swiss rearguard. He was tripped in full flow but the punishment came immediately afterwards, the Norwegian wing-back scoring with a low, swerving shot from the free-kick.
That was that, then. Anfield sat back to watch the expected rout, but everyone had forgotten the home defence's capacity to lose the plot. A long ball was played to Chassot, Liverpool's back five disappeared, and the Swiss striker swerved round James before scoring from a narrow angle.
The Swiss had the advantage now because of away goals and if the situation had persisted for any time tension might have undermined Liverpool's attempts to recover. But they equalised within a minute thanks to a delightful flick by John Barnes and then Fowler added two more from McManaman's passes before Berger embellished the night with a strike just before the final whistle.
"We can sit back now and wait until March," Evans said, looking forward to the quarter-finals. "It gives us the chance to concentrate on the Premiership." And to forget a night that might have gone horribly wrong.
Liverpool (3-5-2): James; Scales (Redknapp, 59), Matteo, Babb; McAteer, McManaman, Thomas, Barnes, Bjornebye; Fowler, Berger. Substitutes not used: Collymore, Ruddock, Kennedy, Warner (gk).
Sion (3-5-2): Lehmann; Milton, Wicky, Colombo; Gaspoz (Vincze, 73), Lonfat (Zambaz, h-t), Vercruysse, Quentin, Sylvestre; Chassot, Bonvin (Buhlmann, 73). Substitutes not used: Yenay, Borer (gk).
Referee: H Strampe (Germany).
Photograph, more football, results, page 31