It wasn't a coincidence that Manchester City produced their best performance of the season in the 3-0 win over Marseille.
For only the second time, Pep Guardiola was able to pair Ruben Dias and Aymeric Laporte together. The first time - Dias' debut in the frantic draw at Leeds - was a sign of things to come, but the Marseille game showed how much Dias has adapted to City's tactics in only a short space of time.
In just 180 minutes alongside eachother, they have already shown that they will be the centre-back pairing Guardiola turns to for big games and when everyone is fit.
The early signs are that Dias and Laporte will provide much-needed stability to the defence, and that has also offered Guardiola a boost in midfield, with less need to protect a back four that can now protect itself. Crucially, this frees up a central midfielder to join the attack, which can stretch defences who are already struggling to cope with City's movement.
One of those midfielders, Kevin De Bruyne, is one of City's undroppables in midfield. Like Dias and Laporte, if he is fit, he plays.
There are three talented options in both of the other two midfield positions - Fernandinho, Rodri and Ilkay Gundogan in the holding role, with Gundogan also capable of partnering De Bruyne along with Bernardo Silva and Phil Foden. De Bruyne, though, has long made that right-side of a midfield trio his own.
Likewise, Raheem Sterling has proven himself as a big game player indispensable to Guardiola. Whether on the wing or covering in the centre, Sterling has added goals in the last two years to an already strong all-round game, and he is crucial to how City attack. His maturity while Sergio Aguero and Gabriel Jesus have been out has only strengthened his position in the side, as has his incredible goal record for a winger and seemingly endless fitness.
Sterling has played in every game this season, but was a substitute for one of those. Only Kyle Walker has started each of City's ten games, plus two for England, and his performance level has shown no sign of dropping.
As Guardiola himself said, Walker is arguably playing the best football of his City career. He's limiting Joao Cancelo, a fine right-back himself, to rotation appearances on the left - just as Walker did with Danilo. Social media is full of posts arguing Walker is the most in-form, all-round right-back in Europe, and on the back of his form in 2020 it's hard to disagree.
For England, he's become so valuable that Gareth Southgate will playing him out of position if he's not chosen at right-back, rather than dropping him completely. He will come up against his main rival for a spot at international level, Trent Alexander-Arnold, next week when City host Liverpool in the Premier League. Barring injury, Walker is one of Guardiola's undroppable players who will surely start.
Along with Dias, Laporte, De Bruyne, Sterling, and of course Ederson, Guardiola now has a core of world-class players who have beaten his ruthless rotation policy despite a backdrop of limited fitness and never-ending fixtures.
It's naive to think these players will play every game, and they will obviously need a rest at some point. However, they have earned a status under Guardiola that means while other positions are always up for grabs, theirs are the first names on the teamsheet for a big game when they are available - like against Liverpool next weekend, for example.
And if City were playing in a Champions League final tomorrow, it's fair to say six of his starting XI would be nailed on.