Fernando Alonso says he feels "fresh and ready" to return to Formula 1 in 2021.

2019 was the Spaniard's first year after 'retiring', but he actually always left the door open for a return in the future.

That future could arrive in 2021, with Spanish media reports quoting him as saying: "I have not finished with F1.

"2021 is a good opportunity and I feel fresh and ready now. It's something I'm going to try," Alonso added.

However, the two-time world champion will be 39 when he returns. He denies it is too old.

"I don't think so. Now, without fuel stops, the races are not so demanding," Alonso said.

"You drive seven or eight seconds slower on a Sunday than on a Saturday. The new 18-inch wheels will also change the way you drive and everyone will be learning that."

As for why he even wants to return, having said when he retired that other challenges now inspire him more, Alonso answered: "F1 is unfinished business because people think I deserved more, especially in recent years.

"In my museum there are many trophies, but none from F1 very recently and that seems a bit strange."

Many believe Alonso has some blame in that, having made some poor decisions during his career. He admits choosing a team for 2021 will also be difficult.

"The only problem with the new rules is that some teams might interpret them differently than others," he said.

"You could join a team that is winning now, but if they make a mistake with the rules, will people say I made a bad decision again?"

He admits to having "many meetings" with Red Bull in the past, and was also asked about a potential race seat at Mercedes.

"They have been dominating for many years and have a strong team," said Alonso. "We will see how they are doing.

"If I come back I will be ready to return stronger, and if I am in the right place, I will win. I have so much confidence in myself that I should win if everything goes well.

"Driving is the only thing in life that I know I can do well," he added.