In a season where Liverpool are threatening to re-write English football's history book, it was perhaps inevitable they would revisit an old chapter in the Champions League.
Previous semi-finals under Jurgen Klopp have been kissed by chaos; a case study in how to put your supporters through the broadest spectrum of emotions. And this was exactly the same. For 75 minutes, at least.
A 7-6 aggregate win over Roma was needed to see the Reds reach their first final in this competition for 11 years in 2018. The following year just happened to require one of the most iconic performances in club history to turn around a 3-0 first-leg deficit to Barcelona too.
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And Liverpool's third appearance in the most glamorous club competition in football under Klopp was achieved through that same white-knuckle ride that is apparently needed to take them there.
After looking more than comfortable after a 2-0 win at Anfield last week, the worst 45 minutes of the season to date had an error-strewn Reds reeling and rocking at the break. A second-half resurgence was needed to see off this spirited Villarreal.
But while this was in-keeping, in so many ways, with Klopp's previous semi-finals, it was very much the breaking of new ground too as they became the first Liverpool team to win an away tie of a European Cup semi-final since 1985.
Such were the conditions in Villarreal on Tuesday, there were murmurings about a potential postponement as fears of a waterlogged pitch were raised. And as the rain continued to batter a sodden and soaked La Ceramica throughout the day, Klopp might have wondered whether fate was attempting to poetically intervene. But even in the near aquatic conditions, Liverpool ensured the Yellow Submarine did eventually sink.
As expected, Klopp made five changes in total as Thiago Alcantara, Fabinho, Trent Alexander-Arnold, Ibrahima Konate and Mohamed Salah all returned from Saturday's 1-0 win at Newcastle.
Villarreal halved their deficit inside five minutes when Boulaye Dia tapped in after Etienne Capoue had steered a clip towards the far post back across the face of Alisson Becker's goal. It was the earliest the Reds had conceded in over four years, dating back to a game with Manchester City in April 2018.
Giovani Lo Celso, somehow, was not given a penalty later in the half after being played through one-on-one with Alisson. The former Tottenham man appeared to initiate the contact but firmly found it before seeing referee Danny Makkelie theatrically wave it off.
If that was a let-off, there would be no reprieve moments later when Capoue claimed his second assist of the night with a cross that found Francis Coquelin at the back post. It was nothing less than Liverpool deserved. They looked like a hollow shell of the team who had previously walked through all-comers since the start of the year.
It was, by a considerable distance, the most disheveled and unorganised 45 minutes of the season and for a team whose mental strength is so often championed - not least by their manager - they looked so easily rattled.
Then it all changed. Klopp sent on Luis Diaz for the anonymous Diogo Jota and the Colombian winger had an instant impact, giving Liverpool an outlet on the left before the influence of their right side of Naby Keita, Mohamed Salah and Trent Alexander-Arnold started to tell.
It was this avenue where Klopp's men found solace as Fabinho ghosted into the box before powering one through the legs of the hapless Geronimo Rulli just after the hour mark.
And as Liverpool finally gained a measure of control and composure they made it 4-2 on aggregate when Alexander-Arnold crossed for Diaz to nod through Rulli's legs again to restore the healthy pre-match buffer.
If the Villarreal goalkeeper will have been disappointed with the first two, the third was a clanger worthy of DVD nightmare inclusion as Sadio Mane got there ahead of him to leave him stranded. The No.10 then skipped by Juan Foyth before rolling it in for 5-2 on aggregate.
Game, set and match, Villarreal knew their time was up.
Jordan Henderson, Kostas Tsimikas and Curtis Jones were sent on for Thiago Alcantara, Keita and Andy Robertson and the midfielders combined almost instantly to make it 4-2 but Rulli denied them.
And what had at first been hoped and then later been expected has finally come to pass: Liverpool will play every single possible game in a top-flight season, taking them up to a whopping 63 for the campaign.
This, their 57th, was never really in doubt once Fabinho leathered it past Rulli, but for far too long, the peril was tangible. Perhaps that is the way it simply must be for Klopp's side at this stage of the Champions League?
The juggling act now is how to make sure that everyone remains as fit and as ready and as enthused as possible after such a long, exacting year. That trick is complicated by the fact that every single fixture is laced with meaning and fraught with danger at the moment.
The Reds boss will want to keep his protagonists peaking in time for the trip to Paris on May 28 but with an FA Cup final to come on top of a Premier League campaign that could yet yield a 20th league title, there is no let-up ahead of the trip to the French capital later this month.
And the magnitude of that fixture - should Manchester City make it to France themselves - is such that it could yet be labelled as the biggest in both clubs' respective histories.
If they are still aiming to seal the unprecedented quadruple on that Parisien night against their main on-field rivals, the team who have spent close to £1.5bn since 2008 in a desperate search for a European Cup to call their own, then that particular argument can justifiably be made.
For now though, Klopp's men can simply sit back and watch it all unfold at Real Madrid on Wednesday night. The chants of "are you watching Manchester" from Reds fans at full time revealed as much. Liverpool are Paris-bound. Allez les Rouges indeed.
