Come the end of the 2017-18 campaign, Liverpool's 5-2 victory over Roma on Tuesday will probably be remembered as the greatest night of the club's campaign -- depending, of course, upon whether they go one better and win the final itself.
It was almost the archetypal Liverpool victory, one of those famous European nights at Anfield where they blow away the opposition with almost illogical levels of pace and power, nights that would be mythical if they didn't happen quite so frequently.
Yet in terms of performance, it probably won't even rank in Liverpool's best five of the campaign. Forget, for now, about the two late Roma goals that cast a peculiar shadow over the overwhelming victory -- Liverpool's performance wasn't one of their best, simply because it didn't need to be. It was just so easy for Liverpool to penetrate Roma's defence repeatedly because of the staggeringly naive tactics used by Giallorossi boss Eusebio Di Francesco.
Yet Di Francesco's approach must be considered in the grand scheme of things, and in relation to Italian football's position in Europe over recent years. For over 15 years now, Italian football has been mocked for two separate reasons. First, because it's still seen as slow, defensive and overly tactical. Second, because their clubs have consistently underperformed in European competition.
The two are, in a sense, related: football has shifted towards teams being more proactive, attack-minded and possession-based, and Italian sides have largely been left behind.
There has, however, been something of a backlash. Maurizio Sarri's Napoli aren't simply overwhelmingly popular amongst neutrals because they're the underdogs, but also because of their style of play. Napoli press well, pass well and, more than anything else, they play at an extremely high tempo.
This has been Italian football's major problem over the last decade in European football -- they're not tactically or technically inferior, but they're completely unable to cope with the speed of the opposition. Think, for example, about the way Gareth Bale and Aaron Lennon ripped apart both Inter and Milan for Tottenham back in 2010-11, or the way Juventus were pressed out of the game by Bayern Munich in 2012-13.
Sarri is the leader in something of a revolution, and Di Francesco is on board too. Roma weren't expected to progress from their Champions League group, up against both Chelsea and Atletico Madrid, but provided a surprise in terms of both results and tactics.
Away at Stamford Bridge, they pressed aggressively and cohesively in a manner barely seen from Italian clubs in recent years. In their famous 3-0 victory over Barcelona they completely outplayed the Catalan side. And suddenly it seemed Italian football had, at last, risen from the ashes. A title fight between Juventus and Napoli, both excellent sides, and a third team into the semifinals of the Champions League; Serie A hadn't seen anything like it for years.
In simple terms, Roma got carried away with their all-out-attack approach, and tried to play against Liverpool the same way they'd played against Barcelona. But the two are entirely different sides. Barcelona are now a structured, narrow and slightly one-paced outfit that can be "got at" through aggressive midfield pressing. Lionel Messi plays just behind Luis Suarez with no threats from the flanks, and therefore a narrow three-man defence made sense.
When the teamsheets were revealed at Anfield, Di Francesco was clearly using the same system. But surely it would be interpreted differently against the speed and width of Liverpool's front three, with Roma effectively using a back five rather than a back three?
It seemed that way in the opening stages, but when Roma pushed forward, so did the wing-backs. Not one at a time, as you might have expected -- with the opposite wing-back tucking inside into a four-man defence -- but both at the same time.
Roma briefly caused problems with overloads on the wings, but more than anything they exposed their three-man defence to the speed of Mohamed Salah, Sadio Mane and Roberto Firmino. There are very few defenders in Europe who could have played that way. Kostas Manolas, Juan Jesus and, in particular, Federico Fazio aren't in that number.
Liverpool had space everywhere: space for Firmino to drop into between the lines, space for Mane to speed into in behind, space on the outside for Salah to collect the ball on the flanks, and even space for Salah to cut inside into for his outstanding opening goal.
The second was typical of Liverpool's approach, Firmino dropping into a classic false No. 9 position to poke through for Salah. It's the Egyptian who gets the Messi comparisons, but Messi's old false No. 9 role is now being played expertly by Firmino with assists like that.
The third was the simplest goal, with Trent Alexander-Arnold tossing the ball into 40 yards of space, Salah sprinting onto it and then ambling almost casually towards goal. Firmino and Mane actually did poorly here, making almost the same run, but Roma's defence was in such a state that they couldn't cut out the pass to Mane. The fourth was very similar, Salah in acres of space and Firmino with a tap-in. Then Firmino added the fifth from a set-piece.
It was a tactical disaster, and the irony is that Di Francesco has spent much of his period at Roma talking about how 4-3-3 is the "ideal formation." There would have been no guarantees that Roma would have coped with Salah and Liverpool better in that system, but it wouldn't have resulted in this complete collapse. Roma essentially played exactly the way Jurgen Klopp would have wanted them to: half-pressing up the pitch.
The two late goals, scored by Edin Dzeko and Diego Perotti with a lovely penalty, added some respectability to the scoreline. Perhaps, considering the comeback against Barcelona, it means the tie is still on.
But in the wider scheme of things, those two goals might have a significant impact upon tactical thinking in Italy, a country which is still largely sceptical of the kind of attacking approach Roma showed at Anfield. A 5-0 thrashing may have dissuaded others from following that template, the performance unintentionally promoting the merits of a deep defensive line and a spare man.
Di Francesco got it wrong on Tuesday night, but it's important to remember that Roma's performances have largely been excellent this season, and his approach is in keeping with the continent's more progressive, modern and successful managers. Roma are on the right path; Italian football is too.
However, there's a time and place, and pressing heavily with a high defensive line -- leaving three-on-three against Europe's quickest attacking trio -- was a hugely counter-productive approach. For Liverpool, it was almost too easy.