Daniel Ricciardo admits he endured sleepless nights contemplating if he’d made the right decision to leave Red Bull and join Renault in 2019.

Ricciardo was expected to re-sign with Red Bull for next year when it became clear opportunities at fellow frontrunners Mercedes and Ferrari were not going to materialise, with Valtteri Bottas already signed on and Charles Leclerc heavily-linked, at the time, to be promoted.

However, the Australian opted to sign a contract with Renault after the Hungarian Grand Prix, brining an end to his 10-year association with Red Bull.

The shock move drew a lot of media attention following the announcement, which Ricciardo admits put his decision into perspective as he underestimated the impact it would have in the paddock.

“At time, I didn’t think so,” Ricciardo told ESPN. “I feel like even if I was to, say, trip and fall over on the way to the car and scratch all my arm, by the time I got in the car it would be blacked out in my head.

“I guess what would have affect – which you probably don’t think at a time – is when you’re away from the track and instead of getting eight hours sleep a night, you’re getting six hours sleep because your brain is ticking… for sure this has some form of an accumulated affect.

“Again, I think I am stronger than that and when I get in the car I am sweet, I am switched on, but maybe it did take a little bit away from me without me knowing.

“For sure there were nights where I didn’t sleep as I should have because I had a lot on my mind. Then that builds up and I was probably not as sharp as I once was.”

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Ricciardo’s season had begun with two sensational victories in China and Monaco, putting himself as an outside bet for title contention.

But a miserable second half of the campaign, with several mechanical failures, saw results fade – ending the year without finishing on the podium after his Monaco win.

When asked if 2018 had been the most frustrating and difficult season of his career, Ricciardo replied: “100%. Even if you ignore the results there was so much going on around it…. Highs and lows.

“Some of the DNFs were crazy but then the same year there was the high of Monaco and stuff like that, so it’s a weird one. It was definitely as intense a season as I’ve experienced, both before and after I decided what I was doing next year.”