Luis Enrique sprang some tactical surprises during Paris Saint-Germain's meeting with Nice last month. Left-back Nuno Mendes was moved to left wing. Centre-back Lucas Beraldo played in midfield. Left winger Kvicha Kvaratskhelia went up front.
The changes helped PSG to a 4-0 win, with Nuno Mendes producing a starring display in his new role and Nice unable to cope with the positional fluidity of their rampant opponent. "We let them play too freely," lamented their head coach Claude Puel.
When asked if he would consider using more "unexpected solutions" in PSG's next game against Toulouse two weeks later, Luis Enrique gave an illuminating insight into his thinking and, more broadly, one of the ways in which elite football is evolving tactically.
"Of course," he said. "It's my dream. My dream is to have 20 players who can play everywhere. Nuno Mendes as a full-back, Nuno Mendes as a winger, Nuno Mendes as a No 9, Nuno Mendes as a midfielder. Everyone except the goalkeeper, that would be my dream.
"You can imagine the opposition manager when he sees the line-up saying, 'But he plays everywhere…!'
"It's a dream. I know it will be difficult to achieve but I'll try."
The team that subsequently dismantled Liverpool over two legs in the Champions League quarter-finals had a more conventional look as Nuno Mendes and Kvaratskhelia returned to their natural roles. But the performances were defined by the same fluidity.
Defenders stepping into midfield, midfielders interchanging right and left, and a front three encouraged to rotate. Ousmane Dembele scored twice in the second leg as the nominal No 9, but he popped up everywhere, finding space for himself or opening it up for others by dragging Liverpool defenders out of position.
The line-up graphics showed Kvaratskehlia to his left and Desire Doue to his right but all three players can operate across the front line. Their Champions League touch maps this season highlight the unpredictability that helps make PSG so hard to contain.
The same flexibility can be seen in the side they now face in the Champions League last four. Vincent Kompany's Bayern Munich, like Luis Enrique's PSG, borrow from Total Football, with players rotating into different positions rather than playing fixed roles.
"Harry Kane doesn't just stand in the box and wait," explained their sporting director Max Eberl in February. "Michael Olise and Luis Diaz don't just play on the wing, one-against-one. Joshua Kimmich switches between right-back and defensive midfield.
"I think that football today is more about creativity. How do I want to play? What do I need to react to? How is the opponent set up? And where are the spaces that I need to exploit? It's no longer the classic, rigid 4-2-3-1 or 4-4-2 formation.
"When you see the tactical formations on television at the start of the match, it's sometimes completely different, because actually, the defensive midfielder and the No 10 drift wide, the centre-backs and full-backs make runs into the centre...
"I believe true specialists who can only do one thing will become increasingly rare, simply because the game is becoming much more dynamic and variable."
The player who best typifies Bayern's Munich flexibility is Konrad Laimer, who joined from RB Leipzig as a midfielder but has since excelled at both right and left-back. His versatility, from game to game but also within games, has made him invaluable.
"Konny is perfectly suited to that," added Eberl. "He started out as a No 10 at Red Bull Salzburg, then he became a No 8 at RB Leipzig. He also joined us as a midfielder, but now he is playing as a full-back, in the way Vinny envisions a full-back."
Laimer's modest status does not match his importance to Bayern Munich. But the same versatility can be found in some of the most valuable players at other elite clubs.
At Liverpool, there is Dominik Szoboszlai, a player capable of operating anywhere in midfield, at right-back, or even as part of the front line. Manchester City are losing Bernardo Silva this summer but have gained midfielder-cum-full-back Nico O'Reilly.
Arsenal have Declan Rice, who is comfortable at No 6 or No 8 and can fill in at centre-back, while his team-mate Kai Havertz can play in midfield or up front and has even been used as a marauding left-back by Germany head coach Julian Nagelsmann.
The best example might be Real Madrid's Federico Valverde, who can play anywhere in midfield or up and down the right flank, always adapting seamlessly to what is required.
His team-mate Trent Alexander-Arnold called him "the most underrated player on the planet" after his hat-trick against Manchester City last month. "There is no flaw in him," he added. "It doesn't matter where you put him," said manager Alvaro Arbeloa.
Zanetti and the secrets of versatility
Valverde sets the benchmark for versatility in today's game.
Luis Enrique, meanwhile, is a fitting champion for it given it was arguably his main characteristic as a player, when he featured in every outfield position, bar centre-back, across spells with Sporting Gijon, Real Madrid and Barcelona, and for Spain.
Javier Zanetti is another.
The Inter and Argentina legend was principally a right-back but also excelled at left-back, as a holding midfielder and in central defence. He covered all four roles during Inter's triumphant Champions League campaign under Jose Mourinho in 2009/10.
"It's very important because it allows you to play wherever your team needs you most," Zanetti, now Inter's vice-president, tells Sky Sports.
"It allows you to have the trust of your team-mates and your manager, and to know that they think you're capable of covering certain positions. I think players today should have that versatility."
The need for it is partly stylistic. Eberl is not alone in thinking the game is becoming more dynamic at the elite level. But there are also practical reasons. As the calendar becomes more intense and injuries proliferate, the value of versatility increases.
There are financial factors in its favour too. "If you have one player who can play in three positions, you don't need to bring in three players for each position," as former Liverpool boss Rafael Benitez put it to Sky Sports in 2024. "These players save you money."
Of course, adapting to different positions and distinct tactical demands comes easier to some players than others. But Zanetti rejects the suggestion that versatility is innate.
"I applied myself a lot," he says. "Whenever I had to play in a different position, the reason I handled it so well because I was always very focused, absorbing all the information my coach gave me. That help from my coaches was very important.
"Tactical intelligence is fundamental, yes, but I developed that throughout my career as a player. I think that, because of my attributes as a player, each manager saw that I had the capacity to adapt to different roles easily. That's why they trusted me."
Not everyone agrees that the fluidity showcased by teams such as PSG and Bayern Munich is indicative football's direction. Some argue that recent trends towards directness and set-pieces are in fact evidence of a game going backwards.
But developing homegrown players with the flexibility to play in multiple positions is certainly a focus for many clubs.
Dan Micciche, a youth development expert who has held roles with Everton, Arsenal, Spurs and England, and is now working as academy manager for Al-Ahli in Saudi Arabia, describes tailoring training sessions and tactics accordingly.
"Exposing players to different positions is more about the outcomes they well get from it, in my view," he tells Sky Sports. "It also depends on individual development plans.
"For example, I remember games at Spurs where we played a midfielder as a centre-back against tall strikers. Why? Because he needed to get better at aerial duels and heading and we know that the opponent were going to be direct."
He agrees that versatility can be coached. "It's about session design where the constraints of the exercises force players into different positions, and about using a playing style which is more Total Football-based where you play a shape not a position.
"There's also a volleyball-style approach where players move around throughout a game and get exposed to different positions, particularly when substitutions are made."
The benefits can be immense, he adds, both for the players and their clubs. But such an approach demands a long-term view. "Most coaches don't do this because it often impacts the outcome of a match and they want to win at all costs."
Of course, young players are driven to win as well as coaches. But devoting time and resource to developing adaptability has clear benefits in terms of longevity too.
Harry Kane has leaned into his playmaking qualities as he has got older, dropping into midfield with increasing regularity then arriving late in the box. Cristiano Ronaldo is still scoring at 41 having transitioned from wide player to out-and-out striker in his 30s.
Going back further, Zanetti provides another example, able to excel at the base of Inter's midfield when his pace and dynamism began to fade in the latter stages of an extraordinary career at the highest level which spanned three decades.
"That was important, without doubt," says Zanetti. "I was lucky enough to play until I was 41 and that helped me a lot, as well as keeping in shape to the required level."
How Luis Enrique, the manager, would cherish a player like Zanetti. But even as his quest for "20 players who can play everywhere" continues, PSG, like Bayern Munich, are showing the value of versatility, and the crucial role it could play in football's future.
Follow the Champions League semi-final first leg between Paris Saint-Germain and Bayern Munich live in our blog on the Sky Sports website and app on Tuesday; kick-off 8pm