Former Sauber CEO Fred Vasseur has confirmed that Alfa Romeo was "aware" the team was in discussions with Audi before announcing its F1 exit plan.
Sauber will race as the Audi factory team from 2026 when the new power unit regulations come into force.
The outfit has competed with Alfa Romeo sponsorship since 2018, with a full naming rights package agreed upon from the following campaign.
But the forthcoming season will be the last of the relationship, as the Italian marque clears the way ahead of a new era for the team.
Asked if Alfa Romeo had been "in the loop" with regard to discussions, speaking to GPFans as team boss prior to his recent Ferrari appointment, Vasseur said: "They were aware.
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"Then they took the decision to stop at the end of 2023, it was their own decision and we respect that."
Perhaps alluding to his then-imminent move to join Ferrari as team principal, he added: "Then we have '24 and '25 but I am not worried at all. You will soon understand why."
Despite the excitement in the F1 paddock to have another major manufacturer join the grid, Vasseur conceded the name above the garage door has little effect on him.
"Honestly, and it is not negative with Audi at all, I am excited by racing, not by x, y and z," he said.
"I love to be on track, to perform and do a better job this year than the year before.
"For sure, the fact we have a car manufacturer with us, to be a works team and run their engine will be extra motivation because we will have more resources but the approach will be exactly the same."
Additional reporting by Sam Hall