Jean-Eric Vergne admits he was bitterly disappointed after being overlooked for the 2014 Red Bull seat, but says it made him stronger.
The Frenchman, along with Toro Rosso team-mate Daniel Ricciardo and Kimi Raikkonen from Lotus, made it onto Red Bull's initial shortlist, but he was the first to drop out of contention.
The seat eventually went to Australian Ricciardo and Vergne admits it came as a blow when the defending World Champions decided not to sign him up.
"It was a disappointment of course not to go to Red Bull. As a racing driver you want to win races and be World Champion, and for this you need the best car - and Red Bull is the best car," he said during Sky Sports F1's Toro Rosso season review show.
"So it was a big disappointment I had to go through. Then I had to look in the mirror and say, 'Why did Red Bull pick him up and not me?' I think that helped me a lot in trying to be better."
The 23-year-old quickly got over the setback to finish the 2013 season strongly and he is confident he will improve further in 2014 after learning some valuable lessons this year.
"There is no other team I'd like to be with. First of all I stay in the Red Bull family and I really believe in the team. We have good plans for next year and the year after," Vergne said.
"I love this sport. Obviously I would love it a lot more if I was running at the front but sometimes you have to be patient. It's what I'm trying to do.
"Probably my biggest problem when I arrived in Formula 1 was to be too impatient. When you arrive from every category since karting you are used to winning everything and to be really in a bad mood when you finish second or third on the podium. I was this kind of guy; I was always fuming when I was not winning a race.
"When you arrive in Formula 1 and you're fighting for P10 in this team it makes things really difficult and it took me a really, really long time to try and understand that it was a really good result to finish P10 or P8 and have a positive spirit."