Fernando Alonso has revealed he considered quitting Formula 1 at the end of the 2017 season.

It proved another difficult season for the Spaniard who finished just 15th in the championship race after skipping the Monaco Grand Prix in favour of making his debut at the Indianapolis 500.

Alonso’s admission comes despite the two-time world champion knowing he would be reunited with Renault for 2018, the manufacturer which powered him to his titles, after McLaren spit with former engine partner Honda.

“I did think about the possibility of changing series and stopping Formula 1,” Alonso told F1 Racing.

“After I did the Indy 500, when I came back there were a couple of races in Austria, Silverstone, when I thought, ‘Maybe next year I could try a different series; I could do full commitment to the triple crown and do Indy and Le Mans and maybe that’s the best thing’.

“But I felt it was not the time for me to step out, not right now, not after these results, not with this feeling.

“I knew I would regret it for the rest of my life and that I would have this bad taste for the rest of my racing career. So definitely I still want to succeed.

“There is unfinished business for me and McLaren together.

“And I think this year is the time all these things will change. I feel pretty sure about that.”

Together with a victory at Indianapolis, an ambition he’s left on hold for 2018, the 36-year-old is also chasing success at the 24 Hours of Le Mans, and has signed with Toyota to compete in the World Endurance Championship.

Winning at Monaco, Indanapolis, and Le Mans, the ‘triple crown’, is a feat only achieved by Graham Hill.

Back in Formula 1, pre-season testing has left Alonso optimistic heading into the new season, though it wasn’t without its problems.

On the opening day he had a wheel nut failure which pitched him into the gravel, while an oil leak and turbocharger issue saw McLaren complete the least number of laps of any team.

Despite the setbacks Alonso is confident he has a competitive package for the coming season, and can once again entertain the idea of a podium finish.

“Back to normality, back to this normal feeling of getting to every grand prix and preparing through practice and qualifying and knowing that you should be in the top five, and if you do well you could be on the podium,” he said of his thoughts ahead of 2018.

“And if you do something really special, you could even be a winner. That motivation and that preparation have been the things I’ve missed.

“These are things that I hope to have this year. That’s the biggest expectation.”

The 2018 Formula 1 season begins next weekend in Melbourne, March 22-25.