Alonso qualified fifth at Suzuka and eventually finished sixth, losing out to the Ferrari of Charles Leclerc.
He managed to stay clear of the Mercedes of George Russell and the McLaren of Oscar Piastri in the closing laps of the race.
He believes that the Aston Martin AMR24 is the fifth fastest car at the moment, and thus he and the team is scoring better results than expected.
“Obviously not fully confident,” he said when asked if he thought he could keep Piastri and Russell at bay. “Because you never know what pace the others will do at the end of the race
“But yeah, I think it was my best weekend, I don't know, inside the top five, ever, for me. I think P5 yesterday in qualifying, that lap, and P6 today in the race is completely out of position. So yeah, very proud.”
Asked to elaborate on his claim he said: “Well, I think we are the fifth fastest team by a good margin to the fourth and good margin to the sixth. We are quite established there.
“I think there is no way to compare us with a Ferrari, McLaren, Red Bull and Mercedes. So that's why to finish P5 and P6 is completely unusual. We did in Australia as well. We finished P6. Here, P6 again.
“Yeah, P5 I think in Jeddah, so we are executing very well, the races - and the others, they are experimenting a little bit with the strategy and other things, and we are capitalising on those. But we need to improve the pace for sure.”
Aston Martin boss Mike Krack backed Alonso’s claim that he and the team are overachieving with the car they have.
“I kind of agree,” he said when asked by Motorsport.com about his driver’s view. “Because when you when you look back, we took the first five races as a reference, to see where we are. And we were, on average, the fifth fastest team.
“Maybe sometimes joined fourth, which means that you fight for seventh to 10th, normally.
“And when you have no quick cars out, you finish in front of them - obviously there is the track position. But to get the track position, you have to qualify well. So from that point of view, I think you have to agree with that statement.”
While pleased with the team’s execution Alonso is adamant that Aston still has to find more performance.
“I think there are a couple of things in the pipeline to improve the car,” said the Spaniard. “I think this first package is just the baseline of what we will introduce later in the season. So we still need to analyse many things.
“But as I said, we are executing very well on Sundays, maximising the points, so even more than what we deserve normally.
“Pit stops were great, actually on the second stop when I saw the green light, and I went, I said, 'Whoa, maybe they didn't change all four tyres,' because for me it felt like the fastest ever! I'm curious to see the time.
“So there are small things here and there that are making it possible to get the result. But I think fundamentally, the pace is not where we want to be. And this is something we need to focus on now.”
