"Marco lost the front end and attempted to save the crash, but unfortunately the inertia of the bike took him onto the inside of the corner just when Edwards and Valentino were passing. There was nothing that they could do to avoid him.
"Today is a tremendously sad day for the entire paddock and for those who love motorcycle racing."
"Ducati, its team and its riders are deeply affected by the tragedy that struck the MotoGP world today, and they gather around the family, friends and team of Marco Simoncelli, who lost his life in a terrible accident during the Malaysian Grand Prix.
"We will always remember Marco for his smile, his enthusiasm, his big heart and for the incredible emotions he allowed us to experience in recent years. He was one of us."
Factory Yamaha Team:
"Yamaha wish to convey the deepest heartfelt condolences and sympathies to the family, friends and colleagues of Marco Simoncelli following the tragic accident today at the Grand Prix of Malaysia. Marco was a worthy competitor and rising star of MotoGP who will be deeply missed by all."
Rizla Suzuki MotoGP:
"All at Rizla Suzuki are deeply affected by today's tragic events and send their deepest condolences to Marco's family and friends during this time of great loss.
"R.I.P Marco Simoncelli, 20 January 1987 – 23 October 2011 - A true competitor."
"Toni Elias, Lucio Cecchinello and the whole LCR Honda MotoGP Team thoughts go to Marco Simoncelli's family, friends and the whole Gresini Racing Team in this tragic moment.
Luca di Montezemolo - Ferrari President:
"I am very sad to hear of the death of Marco Simoncelli," Montezemolo told Ferrari.com. "I was very impressed by his speed, talent and the determination he showed this year. His qualities reminded me of Gilles Villeneuve and now, fate has chosen to link them in this tragic fashion. On behalf of everyone at Ferrari, I offer all our condolences to Marco's family for their loss.”
Michael Bartholemy- Team Manager, Marc VDS Moto2:
"It is difficult to know what to say. We were all devastated by the news that Marco Simoncelli had lost his fight for life and had passed away this afternoon. Sometimes we forget that competing in this sport that we love is not without risk, only to have it driven home by a tragedy like this. Marco was a larger than life character who will be truly missed by all those that knew him. Our thoughts go out to his family and friends."
Indianapolis Motor Speedway:
"We are deeply saddened at the passing of Marco Simoncelli. He was one of the most charismatic figures in the World Championship and had a fantastic future ahead of him in MotoGP. Marco was one of the most popular riders at the MotoGP event at Indianapolis, as his talent on the motorcycle and his ability to connect with fans both were very special. We extend our sincere sympathies to his family, team and fans."
Stefano Domenicali - Scuderia Ferrari F1 Team Principal
“It's hard to express in words the pain felt at the loss of such a cheery character like Marco Simoncelli. Events such as these and the equally tragic loss of Dan Wheldon a week ago in the Las Vegas Indy Car race, remind us how all those who take part in motor sport are always exposed to these risks. One must never drop one's guard, aware that there is nothing one can do against fate.