Real Madrid's pre-season has been full of doubt, especially in defence, yet Casemiro's performances against both Red Bull Salzburg and AS Roma have shown just why he is so important to Los Blancos.
His participation in the Copa America forced Zinedine Zidane to wait until he was able to count on the former Porto midfielder in pre-season, but as soon as he was available, he was back in the starting eleven.
After shipping 16 goals in the first five matches of pre-season, Casemiro's return against Red Bull Salzburg saw the team keep their first clean sheet of the summer.
His presence makes Los Blancos a more solid, serious team, he keeps people in position and is vital to how Zidane wants his team to setup.
Against Roma he was accompanied by Fede Valverde and Luka Modric, but it's the Brazilian international who is the irreplaceable player for the French coach.
Multiple tactical ploys were used over the course of the final two friendly matches from Zidane, but Casemiro will always be part of any setup.
As such a fundamental player for Zidane, those behind the scenes in the Spanish capital are rapidly trying to put the finishing touches to a contract extension for the Brazilian, an issue that will be officially addressed as soon as the transfer window closes.
Many teams are interested in him, especially Paris Saint-Germain, and you never know if he could be the key to unlocking a deal for Neymar.
Florentino Perez's inability to prise Paul Pogba away from Old Trafford has left Zidane frustrated with the midfield options, and this makes any potential Casemiro departure borderline impossible.