In an extremely tight qualifying battle, Alonso's final Q3 lap was good for sixth, 0.363s off polesitter Max Verstappen and only half a tenth behind George Russell in third.
But Alonso slid down the order to finish ninth in the race, being unable to keep up with the Mercedes of Lewis Hamilton and both McLarens, all of which started behind the Spaniard. Behind him, team-mate Lance Stroll was spun around on the first lap but recovered to claim the final point in 10th.
Saturday's race has been been perfectly in line with what the Silverstone team had projected, Alonso explained, after being out of position on the starting grid.
"Today I think is exactly what we expected," the two-time world champion said. "Our simulations were saying that we were around P9 with not much fight in front of us, the top four teams a little bit with too much ahead, and with comfortable gap behind.
"And it's exactly like that. I think I had [Oscar Piastri's] McLaren 18 seconds ahead and the Sauber [of Zhou Guanyu in 11th] 28 seconds behind. So, we were in the middle of no one's race."
If there was any surprise about Aston's weekend, Alonso felt it was about why it was so quick over one-lap, rather than any lingering question marks over its race pace.
"We are lacking pace for sure. Yesterday's laps are something to study – why we were so fast. So, I think the race was normal. What was exceptional was yesterday's lap," he explained.
"[The car] is better. We did improve the top speed, we did improve the fast corners. Obviously, we made some sacrifices in the low-speed stuff."
Aston Martin is also trying to figure out why it was so competitive in qualifying trim when at the previous week's pre-season test it looked like the AMR24 one-lap pace was weaker compared to its race performance.
"This is something we really need to analyse, because obviously you want both," team principal Mike Krack said.
"And in the test, it looked a little bit the opposite. In qualifying we were much, much closer than we really thought. Today was a little bit more what we had expected.
"We need to form this picture with the tracks that are coming, but certainly we were not in a position to challenge the [teams ahead]."
