Alfa Romeo looks to have cured two key weaknesses with its F1 2023 car

Following an encouraging opening day of running for the new C43 at the Bahrain pre-season test on Thursday, both Valtteri Bottas and Zhou Guanyu were left upbeat by some specific areas of progress made over the winter.

Beyond some general aerodynamic and performance upgrades, the drivers are especially boosted by both reliability progress and more rear-end stability, issues that plagued the squad throughout 2022.

Speaking about areas where the car felt much better, Bottas said: "Definitely the rear end of the car has become more stable. This was a weakness last year, especially in the higher-speed corners, so that's good.

"Still we need to fine-tune the balance, especially as in the lower speed we are struggling a bit with locking up the fronts and then understeer. But that is nothing we cannot solve."

Zhou said that improving the back end of the car had been a priority for the designers over the winter.

"It was kind of our main target," he said. "We tried to solve it in the second half of the season but, as we solved it, we lost some car performance because of it. This year we have tried to get back the performance we had early in the season.

"High speed was the weakness we had last year. So we have tried to improve that, which seems to be working well. Now, it seems quite clear the improvement we were able to do."

Zhou Guanyu, Alfa Romeo C43

Photo by: Zak Mauger / Motorsport Images

As well as the car feeling better to drive, the reliable running that allowed Alfa Romeo to get through the day pretty much trouble-free was a huge boost.

The 138 laps both drivers completed on the first day were a total contrast to the limited running that hampered the team's first test at Barcelona last year.

Twelve months ago, it did not manage to complete more than 100 laps per day throughout the opening Barcelona test, even being limited to 32 laps on the first day of running.

Bottas said the reliability progress stood out for him as a critical step that the team appeared to have made.

"The main positive thing is that we didn't have a single issue, which is a huge contrast to testing last year," he said. "So at least we started on the right foot and got some proper mileage which is, at this point, so important."

Asked if he felt the reliability troubles that marred the team at many grands prix last year had been cured, Bottas said: "I feel like all the main issues we had last year from the chassis side were well identified.

"Many of the concepts were changed, like for example the cooling where we had multiple issues. And at least [the first day] shows that we can do more than two race distances without issues. That's good.

"So, I'm confident it's going to be definitely better than last year. And obviously, we did have quite a few issues from the Ferrari side last year. But so far, nothing."