Liverpool are a crimson tide going forward, but a red warning light at the back.
The question people ask of them in the Premier League will not change in Europe. They will succeed or fail on their ability to balance enthusiasm in attack with concentration and structure in defence.
Any team that beats Arsenal 4-0 in one match and loses 5-0 to Manchester City in the next is not suited to the quiet life.
Nor is one that concedes a soft goal inside five minutes on their return to Champions League football. The kind of drama Jürgen Klopp's Reds lay on for their fans is wonderful when the result drops the right way.
When it goes wrong, Anfield will find itself crying out for a bit more organisational rigour around their own goal.
But what a force they are when they attack together, sprint upfield, spread wide, invade the opposition's penalty area. Even without Philippe Coutinho, their £130-million captive who started on the bench, they threatened to overwhelm their Spanish guests - Sevilla - in the first period.
After centreback Dejan Lovren had missed his kick on a cross into his team's six-yard box, and allowed Wissam Ben Yedder a tap-in, Liverpool set about rectifying the error with impressive zeal.
They were in no mood to repeat the indignity of FC Basel two summers ago, when Sevilla took them apart in the second half of a Europa League final.
The 5-0 defeat at Manchester City sent tremors through this club.It could not be passed off as a freakish event, because Liverpool were so easy to pass straight through.
Klopp's defenders are usually the ones who take the heat for messing up at set-pieces, but at City the problem seemed to go deeper. Liverpool seemed oblivious to the threat of top-class passing and movement.
The failure was collective.
But no club has used European football to re-energise the soul quite like them.To fans of other clubs, the whole Anfield "European nights" routine must sound a bit overdone. But be assured: when overseas clubs come to Liverpool, memory and tradition come bursting out on auto-release, and a higher destiny beckons.
With that European heritage now comes a very European coach, known for a particular achievement, and a specific style, at Borussia Dortmund, where the individual quality of his defenders was higher.
It would be insulting to say he has only one idea about how the game should be played, but he sure as hell has a preference for mass counterattacking and playing in the opposition's half...