Liverpool defender Andy Robertson learned a painful lesson at the hands of Lionel Messi after getting a first-hand experience of the magic the Argentina international can conjure.
The Scotland skipper put in at least two crucial challenges, including a perfectly timed sliding tackle in the first half as Messi manoeuvred himself into space in the penalty area for a shot, dispossessing his opponent as he threatened a breakthrough.
He was powerless, however, to stop the little maestro scoring a tap-in from a Luis Suarez shot which cannoned off the crossbar.
And he could only watch in grudging admiration when that was followed with a superb, trademark free-kick to inflict a harsh 3-0 defeat which leaves Liverpool with a mountain to claim in next week's Champions League semi-final second leg.
"I thought personally I did relatively well against him down their right-hand side. But he scores two goals so, for me, that's not good enough clearly," said the left-back.
"I thought the second goal he scored was world class. You could've had two keepers in and we wouldn't have saved it but that's what he can do.
"That's Messi. He's done it for many years now. Fair play to him, he's a world-class player and he conducts himself as a world-class player.
"The second goal was one of the luckiest goals I've been involved in, coming off the bar and Messi taps it in.
"Just as we were getting into the game and the fans were starting to boo and get on top of them and we had them where we wanted them.
"We need something special on Tuesday, but if there is any place to do it it's Anfield."
There can be no dwelling on what might have been – or the gargantuan task ahead – as the priority now is to lift themselves for Saturday's trip to Newcastle.
It is another must-win game as Liverpool seek to keep the pressure on Manchester City in the penultimate match of an enthralling Premier League season which has seen both teams relentlessly register victory after victory.
"We are near the end of the season but we've got three, hopefully four, games left," added Robertson.
"We've no time to have a hangover now; we need to go strong into the Newcastle game first and go again because we can't let our foot off the gas.
"We need the three points and to push them (City) the whole way. There can't be a hangover. Newcastle is our full concentration now."
While their Champions League experience looks likely to come to an end next week, Robertson insists, in the grand scheme of things, it has been another valuable learning curve which can only make them better.
"I think we have developed a really good team," he said.
"We have fallen short but we can be proud of the performance and we just need that bit of luck.
"We are still young and will still learn and be better for it in years to come.
"We can be proud of what we have done this season but we need one big final push now."