Michael Schumacher, the retired seven-time Formula One champion who often braved death on the tracks, remained in a critical condition Monday after an off-piste skiing accident in the French Alps.
The German racing legend, who turns 45 at the end of the week, had been skiing off-piste Sunday with his 14-year-old son in the upmarket Meribel resort when he fell and hit his head on a rock, prompting an urgent evacuation by helicopter.
In an update to reporters on Monday, doctors at the hospital in the southeastern city of Grenoble where he is being treated said it was still too early to make a prognosis on the famous patient.
"He is in critical condition. He is in intensive care, his condition is very serious," Jean-Francois Payen, head of the intensive care unit, told reporters.
Stephan Chabardes, the professor who operated on Schumacher, said the former racer arrived in hospital on Sunday in an agitated state and was not able to answer questions.
His condition "rapidly deteriorated" and he fell into a coma, he told reporters.
Payen said he was operated on and put into an artificial coma, adding he had been partially protected by his helmet.
"If someone had had this type of accident without a helmet, they would definitely not be here," he said.
"We cannot predict the future for Michael Schumacher," the hospital said. "It's too soon to talk about."
Schumacher a 'crazy daredevil'
News of Schumacher's accident stunned the Formula One community and his former teammates joined thousands on Twitter in wishing him a speedy recovery.
"My thoughts are with Michael Schumacher at this tough time.. Michael more than anyone has the strength to pull through this," tweeted British F1 driver Jenson Button.
Schumacher's former teammate at Benetton Martin Brundle wrote on Twitter: "Come on Michael, give us one of those race stints at pure qualifying pace to win through, like you used to. You can do it."
He added that the German was "a crazy brave skydiving/bike racing daredevil".
In his native Germany, fans were anxiously awaiting the next update on Schumacher's condition and the media was awash with the news.
"We're very upset. We know him really well. He's a fighter, we're crossing fingers that he will win this battle," said Michael Viehmann, president of a Schumacher fan club in Kerpen, where the retired racer grew up.
Schumacher's accident comes after several off-piste skiers died or were injured in the Alps, and on Sunday authorities in the Savoie department where Meribel is located asked skiers to be extra "vigilant".
Schumacher, who won the last of his world titles in 2004, definitively retired in 2012 in the Brazilian Grand Prix, in which he finished seventh, after an abandoned attempt to quit six years earlier.
Since his debut in 1991, the German towered over the sport, winning more Formula One world titles and races than any other. He had a record 91 wins and is one of only two men to reach 300 grands prix.
Schumacher's duels in his heyday with Damon Hill and Jacques Villeneuve, fired by an unquenchable competitive spirit, have gone down in Formula One lore.
Schumacher was born in January 1969 near Cologne, Germany, the son of a bricklayer who also ran the local go-kart track, where his mother worked in the canteen.
By 1987, Schumacher was the German and European go-kart champion and was soon racing professionally. In 1991 he burst into Formula One by qualifying seventh in his debut race in Belgium and a year later he was racing for Benetton, where he won his first Formula One grand prix in 1992.
Really sad to hear about #Schumacher Hope he makes a quick recovery. Can't believe I've been skiing off piste all these years sans helmet.— Omar Abdullah (@abdullah_omar) December 30, 2013
All my thoughts with Michael Schumacher and his family. Be strong as you were in your racing days, Schumi!!! Fight for life! #Formula1— Liga Stirna (@liga_stirna) December 30, 2013
He joined Ferrari in 1996 and went from strength to strength over the next decade, dominating the podium, before trying to retire the first time aged 37.
During his retirement he survived a horror accident that knocked him out when racing a motorbike in Spain.
That time he was released from hospital after just five hours.
But the father of two could not resist the lure of the track and in 2010 he signed a three-year deal with Mercedes.
But slower reflexes and a less competitive car meant Schumacher could not reproduce his former glory and he quit for good in 2012. His helmet had a message for fans: "Life is about passions -- Thank you for sharing mine."