|Rosberg had to grow some bigger ones|
Having shocked the world of motorsport by announcing his retirement, Nico Rosberg has revealed he didn't know if he "had the balls" to go through with it.
Five days after winning his first Drivers' Championship, Rosberg broke the news that he was retiring from the sport.
It was a decision that he in the build-up to last Sunday's championship triumph in Abu Dhabi but one he wasn't entirely sure he could follow through on come Monday morning.
He did, informing his family and Mercedes before later telling Hamilton.
"The thing that gave me most clarity before Sunday's race was the thought of ‘I'm actually going to win here today, this is going to be my last race so let's take it all in'," Rosberg said.
"It took away some of that massive pressure, so that was very nice.
"That finished as soon as the lights went off because after that it was the most intense and crazy and tough race of my life.
"Then it was just a process on Monday, I didn't know if I had the balls so it took a bit of time.
"But I'm going through with it and I'm feeling great."
Having previously cited his desire to spend more time with his family as one of his reasons for retiring, the 31-year-old explained that he just isn't willing to give the same commitment to another title fight as what he gave this past year.
"I've achieved this childhood dream now and I'm not willing to do that sort of commitment again for another year.
"I'm not interested in coming fourth or whatever. I'm a fighter and I want to win.
"I'm not interested to do that again, I don't want to do it again so I decided to follow my heart which told me to stop there, call it a day and go on to other things."
Asked if there was a possibility that he could one day return to F1 racing, the 2016 World Champion replied: "Definitely not. Finished. Done. End of story."
Jackie Stewart believes Nico Rosberg showed "courage" and "wisdom" in his decision to retire for Formula 1.
Rosberg shocked the Formula 1 fraternity on Friday when he announced that he was retiring from the sport, five days after winning the World title.
Having fulfilled that childhood dream, the Mercedes driver cited his desire to spend time with his family as one of the reasons for walking away.
"I think it's great news," Stewart told Telegraph Sport. "Very few drivers have had the courage to do what Nico has done. Or the wisdom.
"To come through without a drop of blood off his body, to win the World title, and then to say 'that's it, I'm done'. I just think it's terrific."
He added: "Knowing Nico, I do not believe this is a decision he will have taken lightly. He is highly intelligent. I'm sure he is financially comfortable.
"What is he? 31? That is three years younger than I was when I retired. Knowing when to retire is one of the most difficult things in life. It seldom happens as you want it to. Getting to walk away on your terms.
"He has obviously had a very stressful season. There hasn't really been harmony between him and his team-mate. That may have played a part – I don't know. He is married he has a small child.
"Time will tell whether he has called this right. A lot of people have semi-retired and then come back. That has usually proved to be a mistake.
"I'm sure he has not taken this decision lightly, though. I would just like to congratulate him on a terrific career. It has been an absolute pleasure watching him. I congratulate him on his decision."
Asked whether safety in Formula 1 played a role in Rosberg's decision, Stewart replied: "It's definitely much safer now than it was in my day. Safer than it has ever been. But motor racing – as it says on the back of the ticket – is a dangerous sport.
"We saw with Fernando's appalling accident this year [in Melbourne] – although he was able to walk away – how close drivers are to serious injury.
"In real terms you are only ever a few milliseconds away from life or death. When looking at it realistically, you have to admit that you could lose your life.
"I was very lucky to leave on my own terms, as World Champion. I enjoyed that privilege. Others were not so lucky. Jim Clark didn't. Jochen Rindt didn't."