Liverpool‘s dismantling of FC Porto at the Estádio do Dragão sent a number of messages to the teams still in Europe's elite competition.
The Reds weren’t overawed in their first knockout match in the Champions League since the 2008/09 season; Sadio Mané put in a performance to remind everyone why he was the main man at Anfield last season and why discounting him would be naïve. With club record signing Virgil van Dijk marshalling the defence they've got to be serious contenders for ol' big ears.
But perhaps the most important message to come from the 5-0 win was that, in Andrew Robertson, Liverpool have found a solution to a problem which has plagued them since the inception of the Premier League.
The 23-year-old ex-Hull City left-back announced himself on the big stage. Fans of the Merseyside club had seen glimpses of what he could offer since his arrival in the summer. But up until the outing in Portugal he hadn't been able to showcase everything in a single match.
He was a marauding menace down the left flank going forward but still managed to execute the defensive part of his role perfectly. Robertson was instrumental in the win over Sérgio Conceição’s men.
Robertson saw a lot of the ball, only van Dijk attempted more passes, and was breaking the defensive lines on a regular basis. The 20-cap Scotland international finished the match having completed 87 per cent of his passes. He linked up well with Mané down the left, with the Glasgow-born defender finding the Senegalese speedster 21 times throughout the match.
Alberto Moreno, the man keeping Robertson out of the team at the start of the season, benefited from an understanding with Philippe Coutinho. And now Robertson's found a rhythm with Mané on the left. For a fluid football team it's all about relationships on the pitch.
He was creating space for team-mates, picking the right passes and, unlike many of his other matches this season, he had an end product.
Earlier on in the season it was clear that Robertson needed more time with manager Jürgen Klopp on the training pitch. He was determined to get the ball into the box at any given opportunity and more often than not it resulted in a soft turnover of possession because Liverpool weren't set up for it.
There was a period of transition. Robertson was adapting to what Klopp wanted from his left-back and as a result his final ball suffered. However, a positive was the fact he was getting into dangerous areas on a regular basis. Against Porto he had it all. There was a variation to his game. In just over six months with Klopp, he's matured. It's telling that despite seeing a lot of the ball he attempted just two crosses.
On another day both of those are finished off and he ends the match with two assists to his name. The first needed a last-gasp challenge from a Porto defender to prevent Roberto Firmino from heading home. The second was clipped over the Porto defence and into the path of Mané who toe-poked the ball over just before he fired home his third of the night.
But it shows he's no longer a crossing machine. Instead he's added many more strings to his bow. It's evident when looking at his stats which show he's now averaging four fewer crosses per 90 minutes while playing more passes.
Building on a solid platform
Robertson's overall performance was even more impressive given he'd just come off the back of an underwhelming showing against Southampton. He was targeted by Mauricio Pellegrino's side and had it not been for Loris Karius' performance between the sticks a lot more would have been made about it in the media.
However, it showed great mental strength to put that disappointing performance behind him to put in his best performance for Liverpool. He fully justified Klopp's faith to start him over the more experienced Moreno. Making your Champions debut in a knockout match in what could've been a hostile environment isn't the easiest of tasks.
But Robertson made it look like a normal training session. It shows that he's a player who doesn't let the big occasions get to him and for a team like Liverpool that's invaluable.
The Reds boss praised his No.26 afterwards, telling Liverpoolfc.com: “It was really good. The whole package, offensively and defensively, was really good. I would say it was his best game.
“We didn't speak before the game about his debut, we handled it like business as usual, and he did really well.”
Liverpool haven't been blessed with reliable full-backs in general but they've had more joy on the right side than they have on the left. Markus Babbel, Alvaro Arbeloa and Steve Finnan were all dubbed as Mr. Reliable for the Reds on the right while only really Fabio Aurelio managed to put in a similar level of performance on the left. However, the Brazilian was far from reliable due to his injury record.
John Arne Riise was famed for what he did going forward as opposed to what he could do in the defensive third and that caused problems on occasion. José Enrique had similar problems.
Fielding Andrea Dossena and Paul Konchesky at No.3 prove Liverpool have had issues filling that role. But in Robertson they now have a player who can do a job for the best part of a decade if he continues to progress the way he has been.
Goal machine Mohamed Salah has been declared the bargain of the summer already but, at £8million, Robertson has to be a close second.