Nothing happens by chance.The Arsenal-Real Madrid statistics explain why the final score was 3-0.
The clearest conclusion from the match numbers is that Arsenal ran more and sought the final victory better.
The quality of Real Madrid's players is outstanding, but if they don't run, the forces are equalized with anyone. Even with Arsenal.
It is the coach's task to make them understand that talent is not enough; they must at least exert themselves as much as the opponent.

Real Madrid Players Don't Run
Arsenal players covered 70.56 miles (113.56 kilometers) during the 90 minutes of play. Real Madrid's, 62.87 (101.16). That is, they ran more than 7.46 miles (12 kilometers) more than the white players.
An unacceptable difference that justifies the final score difference. Assuming Arsenal will exert themselves equally at Bernabéu, Real Madrid will have to neutralize the 7.46 miles (12 kilometers) difference in the return match. More than one per player.
More concerning is that in the other match of the day, Bayern Munich-Inter Milan, the players who participated ran 74.56 and 75.81 miles (120 and 122 kilometers). 12.43 miles (20 kilometers) more than the white players!
But there are more statistics that can embarrass more than one Real Madrid footballer. The white team, which had to control the match, completed 376 passes, compared to Arsenal's 438.
Ball possession was 54% for Arsenal and 46% for Real Madrid. Arsenal took 5 corners, compared to Real Madrid's 3.
The English team shot 12 times on goal, and 11 on target. Real Madrid only registered 3 shots on goal.

Vinícius and Rodrygo's Poor Match
Arsenal stole 34 balls and Real Madrid 26. And the white team already accumulates two consecutive Champions matches without scoring.
Rüdiger didn't win a single duel against the English players and Real Madrid didn't complete a single combination in the area, as explained on El Chiringuito.
Mbappé won 5 duels and shot twice on goal, while Vinícius and Rodrygo were left with zero in both aspects. Vinícius only managed to dribble and win a duel on 1 occasion out of 6 attempts.
With these statistics, it wasn't easy to get a positive result from Fly Emirates. There is hope that Carlo Ancelotti will manage to motivate his men for the return match and that the landscape will be different.