Van Dijk lifts defence as memories of Seville collapse are banished
You could argue the real test for Liverpool began after 53 minutes in Porto. Those three-goal leads away in Europe have been notoriously tricky.
When Roberto Firmino delivered what is becoming a trademark back-flick assist, triggering the rapid counter that enabled Sadio Mane to extend the visitors' lead, in normal circumstances you could be forgiven for pondering who Liverpool might meet in the quarter-final.
Then you remind yourself this is Liverpool, a side adept at transforming positions of superiority into discomfort. Even when 2-0 up at half-time, Jurgen Klopp's team-talk needed the repetition of one word, presumably with increasing volume. "Seville," he could say to his players. "Seville, Seville, Seville." It was there - Liverpool's last away trip in Europe - they led 3-0, initially taming a raucous environment. They left without victory 45 minutes later.
In the group stage they could accommodate such carelessness. Not now. We know how good they are going forward, but how much had they learnt at the back? Plenty, it seems.
Klopp's conviction this would be a sturdier Liverpool was vindicated. He saw a side equipped with an invigorated goalkeeper, Loris Karius. And a side solidified by Virgil van Dijk, the Dutchman recruited precisely for games like this; an intimidating venue where nerves are tested as much as skill.
Van Dijk's demeanour must feel like a relaxation therapy to those around him. He was stress-free, as if enjoying a casual five-a-side with friends. He does not run; he struts.
There were growing signs he is feeling more comfortable in the Liverpool shirt at Southampton last weekend. Maybe the Dutchman feels particularly at home in the - brilliant orange - strip of his homeland. The sight of him pinging 45-yard diagonal balls to Trent Alexander-Arnold and Mane sent the clearest early signal the centre-back would not be fazed by his Champions League debut for the club. But it is his capacity to turn the potentially worrying into the mundane that may prove his most valuable asset.
On three occasions in the first 20 minutes Porto sent long set-plays into the Liverpool penalty area. Twice Van Dijk headed clear. On the other occasion it was Dejan Lovren intervening - the Croatian already looking twice the player in Van Dijk's company.
Given historic palpitations when the ball so much as threatens to go for a corner against Liverpool, such matters cannot be taken lightly. Liverpool exuded firmness.
They knew what to expect if the home crowd rediscovered their voice and once Porto coach Sergio Conceicao had reminded his players of Liverpool's previous vulnerabilities. Arriving in Portugal, only once since February 2011 had Liverpool kept three consecutive clean sheets on their travels. This was a record they hoped to replicate here.
Porto, meanwhile, went into the game having failed to score at home only twice in the past year. They have 84 goals this season.
Conceicao was asked beforehand if he saw Liverpool's back four as the weak link. He was diplomatic, but would have reminded his players of Liverpool's experience in Spain as much as Klopp. He, like others, may start to revise opinions.
Mane's completion of a hat-trick, as well Firmino's deserved contribution to extend Liverpool's lead in the second half, ensured there would be no momentum swing this time. Liverpool were exceptional everywhere, attack and defence. If they maintain that combination at both ends, they will go deep in this competition.