Alonso took his first podium in seven races in last week's Brazilian Grand Prix after coming out on top of a thrilling battle with Red Bull's Sergio Perez on the last lap.
With team-mate Lance Stroll fifth, it was a return to form for Aston Martin after impressing with six podiums across the first races before fading away into midfield obscurity following the summer break.
Its downturn in performance reached a nadir in the first two races of the Americas triple header, with Alonso and Stroll eliminated in Q1 at Austin, though Stroll benefited from two disqualifications to grab seventh in the race.
In Mexico, Alonso qualified 13th and Stroll took a pitlane start after qualifying in 18th, before both drivers retired from the race.
Alonso explained that "painful" experiments to find directions for the 2024 car led to the team's worst form of the season.
"I think we've been struggling for a few months, but the last two races were probably quite painful," Alonso said after securing his eighth podium of the campaign, which has given Aston an outside chance to still beat McLaren for fourth.
"We had to experiment a little bit on a few things on the car to really understand the direction that we were going and we have to go for next year's car as well, so those races were painful, especially Mexico.
"We were very slow as a team, [but] it was nice to see everyone in the team very focused, the determination in the team was so nice from the outside to see and to go deep in the analysis and get back stronger in Interlagos."
After finding the right car configuration for Brazil the Spaniard is hopeful the final 2023 races in Las Vegas and Abu Dhabi will more closely resemble Sao Paulo than the previous two weekends.
"I think so. At least closer to these than Mexico, that's for sure," the two-time world champion said.
"I think there are a couple of things that have been understood inside the team and the direction to go. We had some hopes for this race and they proved to be right.
"And now, why not be competitive in the last two? I don't know [about] the level of the podium. But hopefully, in the mix, that will be a happy place for us."
He added: "I was a little bit concerned, no doubt, for the last few races and maybe the final part of the championship and now I cannot wait to go to Vegas. So, it's a very different energy when you have a performing car."