Selfishness is a key asset for success in Formula One, according to McLaren's Fernando Alonso.

In an interview with the official McLaren website, Alonso -- who is considered to be one of the best drivers on the current grid -- said ruthlessness is one of the most important qualities an F1 driver can have.

"You need to have no heart," he said. "You are not enemies with the other drivers, but you have to focus on yourself to win. If you can 'hurt' someone by getting an advantage over them, that's even better."

The Spanish two-time world champion is currently 13th in the driver standings after struggling for results since he returned to McLaren last year. However, he says the feeling of driving an F1 car keeps him in the sport despite being uncompetitive at the moment.

"I am a competitive person and competition is important in F1, but I don't race in F1 for the competition. I can get that in other areas of my life, like cycling and playing tennis - or racing my mother to the supermarket. The reason I race in F1 is because the cars give me a feeling that I can't get anywhere else. It's unique."

Alonso compares the feeling to driving an extreme go-kart, but single out one big difference.

"It's hard to explain what this feeling is like because nothing else comes close to F1. Your brain has to re-set every time you get in the car because things happen so fast. If you haven't driven an F1 car for a few weeks, the level of performance takes you by surprise.

"I go karting to enjoy the competition; I drive in F1 for this feeling. The driving styles in karting and F1 are quite similar, but nothing unexpected happens in a go-kart. Your brain is never taken by surprise. You can predict everything that the kart is going to do.

"That isn't the case in F1, where you're taken by surprise all the time. When you hit the brakes, your brain takes 0.2s to catch up. That's a very nice feeling; that is the feeling."