Sergio Perez was given only a few hours notice that he was to be replaced at Racing Point next year by Sebastian Vettel, the Mexican driver said on Thursday.
Perez, who had a contract for 2021 and believed the team wanted him to stay, learned his fate during a phone call from team owner Lawrence Stroll on Wednesday, shortly before his departure was confirmed.
The Canadian billionaire told him the team was going "in another direction".
"I didn't expect that. It is how it is," Perez told a news conference on Thursday ahead of this weekend’s Tuscan Grand Prix.
Until then, said Perez, "nobody told me anything".
Perez announced his exit, after seven years with the Silverstone-based team, on social media later Wednesday and Vettel was confirmed as joining on a multi-year contract starting in 2021, with the re-branding of the team as Aston Martin, on Thursday morning.
"Nobody told me anything, but I already knew and figured out a couple of things," said Perez.
"Final confirmation came yesterday. It's fine. Seven years with the team -- I know everything has a beginning and also an end.
"We still have nine races to make each other proud."
Only four weeks ago at the Spanish Grand Prix, Perez quashed speculation that he was to be replaced by four-time champion Vettel.
He felt it was only a "matter of time" before the team confirmed in public the feedback he was being given about him continuing with them in 2021.
"That was the feedback that I was getting, that the team wanted to keep me and so on," he explained.
"There were some discussions in the background, about contracts and so on, that I'm not willing to disclose because I think those things should remain between the team and myself.
"There were a couple of things in the contract that we went through…. In the end, they officially told me yesterday that I'm not continuing."
- 'I understand it' -
Perez signed a three-year agreement last season and had a contract for 2021, which together with the team's apparent desire to keep him persuaded him not to seek any alternatives.
He was reluctant to criticise Racing Point's handling of the situation too forcefully but suggested that he could have been given more clarity.
"I understand it. It's the negotiations going on," he said.
"They probably took longer than I thought… Probably, a bit more clarity would have helped regarding my future as well.
"Then I would have looked for a plan B, which probably wouldn't have changed anything."
Perez, who now has no seat for 2021, said he wants to stay in Formula One next year with a competitive team.
"I think everything is an option right now. My main target is to remain in F1. I feel that I'm still very young and hungry and want to carry on, but it has to be the right package.
"A package that really gives me the maximum motivation to give 100 per cent every single lap and also a long-term project, targeting 2022, because then I expect the rule change to play a major effect."