Motorsport witnessed its second death from a crash, in the space of a week, after Italian Motorcyclist Marco Simoncelli was killed in a crash at the Malaysian Moto GP on Sunday.
The 24-year-old rider lost control over his bike, on the second lap, and slid across the track at Sepang, while being hit by Colin Edwards and then Valentino Rossi, who were riding behind him.
The Gresini Honda rider's helmet came off during the collision, and he was immediately taken to the medical center for treatment. Sadly, the injuries he sustained were too serious, and he eventually succumbed to death.
The race was called off by the organizers, after they realized the seriousness of the accident.
A message on the MotoGP Web site read: Marco Simoncelli succumbed to injuries sustained in Malaysia.
Simoncelli's death is the first in Moto GP since Japan's Daijiro Katoh died during the 2003 Japanese Grand Prix.
Tributes flowed in for the Italian, who won the 250cc world championship in 2008, taking the crown in Sepang. He then went up to MotoGP in 2010 and managed an eighth place finish overall last season.
The newly crowned champion Casey Stoner admitted he feared the worst after the crash.
As soon as I saw the footage it just makes you sick inside, the Australian told BBC2. Whenever the helmet comes off, that's not a good sign.
I'm so shocked and saddened by the loss of Marco, he added. When things like this happen it reminds you how precious life is. All I can say is how sorry I am for Marco's whole family. I can't imagine what they are all going through, and our thoughts and wishes are with them at this time. I hope they all stay close and pull through this tragedy together.
The British MotoGP rider Cal Crutchlow wrote on Twitter: RIP Marco Simoncelli! A great rider and all around nice guy. My thoughts are with all his family & friends. I will never forget today.
Repsol Honda's Spanish rider Dani Pedrosa said: In a tragedy like this there is not much to say. I just want to give my condolences to his family and all the people who love him. I've been with his father and all we could do was hug, nothing else matters.
It was a fatal accident and everybody in the paddock remains in shock.
Many times we ourselves forget how dangerous this sport can be and when you lose people on the way, nothing has any meaning. It's clear that we all do what we like, what we love, but on days like today, nothing matters.
Repsol Honda rider Andrea Dovizioso said: I watched the images and I'm shocked: In a race you fight and push hard, and disaster is often around the corner.
Marco was a strong rider, and he always pushed hard. We raced together since we were kids. I saw him always pushing to the maximum, he crashed many times, but without major injuries, he seemed invincible. What happened today seems impossible.
The Formula One driver Mark Webber wrote on Twitter: RIP Marco. A special talent that will be missed ... Thinking of your loved ones, and all the motogp paddock ... Mark.
Great Britain's Jenson Button wrote on his Twitter account: RIP Marco ... Such an exciting talent lost. My thoughts are with his family, friends and everyone involved in MotoGP. Motorsport can be so cruel...