So how do you solve a problem like Lionel Messi? The truth is, it's probably impossible. Liverpool head to the Nou Camp tonight to face one of the greatest players of all-time and, while Barcelona are a fine side with some great players in their line-up, one player stands alone as their match-winner in chief.
Luiz Suarez and Philippe Coutinho will be keen to impress as their take on their former club in one of the most eagerly anticipated games of this season, but Messi is the maestro who can turn this tie on his own.
You can't really man-mark him as he has proved he can overcome that kind of challenge, so it is a question of stopping the ball getting to him and when he has it under his spell, jump on him as quickly as possible.
That's easier said than done because for the last decade and more Messi has been the outstanding player in the game and the consistency of his brilliance over that period is arguably his finest quality.
The Liverpool players should relish this challenge against Messi and Barcelona because, for me, there is no better stage to perform on than the Nou Camp.
I played there three times and scored six goals. It's a record I tell my grandchildren and I'm not sure they entirely believe me, but it's a record I'm very proud to have.
Scoring a winner at the Nou Camp is one of the highlights of my career and, hopefully, a Liverpool player gets a chance to add that entry onto his record after what should be a cracking match between two attacking teams tonight.
I'm a pessimist when it comes to my former club, but they have a chance in this semi-final tie if they play as we know they can and keep the tie in the balance heading into the second leg at Anfield.
The Barcelona players have proved themselves time and time again on the biggest stages in the game and have generally come out on top, but they have not experienced a special European night at Anfield. I will be interested to see how they handle it.
The noise that stadium and those Liverpool fans generate on European nights is second to none and, while we all know how good Messi and his pals can be, will they be able to perform at their best if they are under pressure in the second leg of this semi-final shooting onwards the Kop?
I have my doubts, but Liverpool need to get them into that position and that means producing a professional performance in Barcelona and trying to nick an away goal or two. We have seen some truly shocking performances from this magnificent Liverpool team on their travels in the Champions League this season, with their three defeats in the group stages all coming amid sub-standard displays.
Liverpool can have no excuses this time. The Premier League game against Huddersfield game turned out to be little more than a training session on Friday night at Anfield and that was perfect preparation for Liverpool ahead of their trip to the Nou Camp.
None of Klopp's key players got injured and they have had plenty of time to freshen up any tired limbs for a tie Liverpool should not fear against a team crowned as Spanish champions last weekend
That will not do against Barcelona and, with the Premier League title now appearing to be beyond Liverpool, I expect to see them at their best this evening.
My prediction? A scoring draw that will pave the way for a wonderful occasion at Anfield in the second leg next week.