Through the castle section, Leclerc was finding eight tenths Alonso couldn't match — and by the final runs, you could see it in the Aston Martin's lines.
There's a moment on Fernando Alonso's onboard from his final qualifying lap where you can see him place the Aston Martin exactly where it needs to be through Turn 8 — tight to the inside, carrying speed — and the car just doesn't respond the way he needs it to. By lap 19, he knew. Charles Leclerc was finding eight tenths through the castle section that Alonso simply couldn't match.