Fernando Alonso says he will "give it my all" in Formula 1 next year even though he knows he will not have a winning Renault.

The two-time world champion is ending his sabbatical in 2021, but he insists that his main focus for now is the Indy 500.

"I have been watching the F1 races and looking ahead to Indianapolis, which is my challenge this year," the Spaniard is quoted by Marca.

"It is difficult due to the situation with infections in the United States and difficulties with travelling. There are no flights, we need permits, but it's looking good to get there and do the race," Alonso said.

"In September I will then look at F1 and next year, looking forward to having another adventure."

However, with Alonso's mercurial personality now notorious in the F1 paddock, the 38-year-old insists he knows very well that winning will not be possible in 2021.

"Next year's cars are going to be the same as we are seeing now, so I am aware of where Renault may be and that we are not going to fight for the front positions," he said.

"But the work of trying to improve for 2022 with a strong team and a strong environment is exciting. Anyway, when I close the visor, I don't care if it's for tenth, seventh or fourth, it will always feel like the last corner of the world championship."