"It's like going to watch the Rolling Stones without Mick Jagger being there," said Sky Sports pundit Jamie Redknapp at halftime of Bayern Munich against Barcelona about the Catalans sans Lionel Messi.
And, as a second swashbuckling performance in a week from Bayern sent La Blaugrana crashing out of the Champions League, courtesy an embarrassing 7-0 aggregate scoreline, those words rung true.
The Bavarians smashed those statistics into smithereens.
Barcelona's results in the past three years without Messi, prior to Bayern's 3-0 win when he didn't make it off the bench, are actually very impressive.
In the 17 games which haven't featured the four-time Ballon d'Or winner, they have won 16 and drawn one.
Hidden away in that fact is that those matches were either occasions when they chose to leave Messi out or games which lacked significance.
Wins at San Mames against Athletic Bilbao and at La Rosaleda against Malaga read the most impressive, but those matches were over two years ago.
The truth is, nobody knew how a Messi-less Barcelona would cope.
And there is half of the problem. Having him present for all of the defining matches of their period of domination has allowed, indirectly, his colleagues to depend on him.
Andres Iniesta, Xavi Hernandez—the list goes on—still rank among the world's best players, yet without the man they have come to rely on, things have become a little flat, a little tougher.
The second leg against PSG provided a glimpse of what Barcelona look like without the Argentinian.
Before Messi virtually introduced himself from the bench, the French side's defense looked organized and in control. Once he appeared, two things changed.
First of all, there was a very evident psychological boost, a spring in the step, embraced by his teammates, which, in turn, seemed to worry the Parisians.
Secondly, his mere presence injected caution in the opposition.
Players were attracted to him through wariness, and Barcelona's equalizer in that game came from him drawing in defenders before passing the ball to David Villa, who teed up Pedro Rodriguez. Both, thanks to Messi, had been allowed more space to work in.
Jupp Heynckes and his brilliantly assembled squad would have been on the right end of the psychological boost when they learnt that Messi was not able to start at Camp Nou on Wednesday night.
Barca looked to begin the game with a purpose, but without Messi—who has 58 goals this season, over 40 more than the club's next top scorer—lacked a cutting edge.
Once Arjen Robben gave the German side the lead on the night, they gave up the ghost; both Iniesta and Xavi were substituted.
Barcelona are not a one-man team, nor is this the final whistle for a generation of players who have won everything—a philosophy is not thrown away over night.
It is, though, a wake-up call. It is the start of plenty of work—on an off the pitch—over a busy summer, in which they'll do well to make themselves more prepared for the proposition of losing Lionel Messi to injury.
Just in case.