"Devastated to hear of the death of Marco Simoncelli, one of the best of our generation. Thoughts go out to his family. RIP Marco."
"Have a safe trip Sic. Words can not explain the suffering."
"RIP Marco. Our sport has lost a great rider and all round great guy. My thoughts are with his family.
"I was fortunate enough to be team mate to Marco in 2002. He was a genuinely fun guy and taught me my first unrepeatable Italian!"
"Stunned. Devastated. Huge huge loss for MotoGP and the world."
"Devastated to hear that Marco Simoncelli has died... the guy was a breath of fresh air in MotoGP.. Can't believe it."
"So so sad! Absolutely terrible and heart breaking when this happens in our sport! All my regards to MS family and close friends :("
Juan Pablo Montoya:
"RIP Marco Simoncelli. he was such a nice guy. My thoughts and prayers to his family and all his friends."
"Quality vs Quantity in life. We could all learn a lesson here. Live w/the passion Simo raced. Never know when your # is pulled. Ciao Sic"
Taka Horio - General Manager, Bridgestone Motorsport Department:
“Today we are left devastated. Our thoughts and prayers are with Marco's family at this terrible, terrible time, and with his team. Words can do no justice to the emotion we are all feeling. The MotoGP family has lost one of its bright stars, a genuine character whose larger-than-life persona, charisma and unstoppable spirit were infectious, and we've all lost a great friend.
"We worked closely with Marco for his first two years in MotoGP and it was clear that he was a true racer, something he proved again and again this season. Determined to the end, and a great showman. His ascent through the field in just two seasons has been fantastic to watch, testament to his raw talent, ability and dedication to the sport he so loved. We remember fondly the tenacity and spirit with which he raced, and he will be sorely, sorely missed.”
Shuhei Nakamoto - HRC Executive Vice President:
"I just don't know what to say, words escape me. Marco was a very nice guy and a very talented rider. Sometimes I was a little harsh with him, for example after his first MotoGP podium in Brno when I told him: "Lucky podium!" and he was so angry... but I wanted to motivate him as I knew he was able to do even more. I was thinking that when he won his first race we would have been able to celebrate together... Now I just want to say thank you to Marco, for what you gave me and pass my sincere condolences to his family and this very sad time".
Monster Yamaha Tech 3:
"The Monster Yamaha Tech 3 Team and Tech 3 Racing Moto2 team extends its deepest condolences to the family, friends, and colleagues of Marco Simoncelli, who succumbed to injuries he received in this afternoon's Malaysian Grand Prix.
"Monster Yamaha Tech 3 rider Colin Edwards was involved in the second lap incident and he suffered a dislocated left shoulder. The American has left the Sepang International Circuit to begin his recovery at home in America and his thoughts and prayers are with Simoncelli and the Gresini Honda family.
"RIP Super Sic - A much-loved star on and off the track."
Jorge Martinez 'Aspar':
"What has happened today is immensely sad. It should be said that every Friday before a Grand Prix, the Safety Commission convenes at 5pm with all the MotoGP riders to evaluate safety issues at all Grand Prix circuits.