Welsh rider Chaz Davies took victory in race two at the World Superbike round in Thailand as defending champion Jonathan Rea had to settle for fourth.
Rea's fellow Northern Irishman Eugene Laverty suffered a broken lower pelvis after crashing out early in the race.
Aprilia boss Shaun Muir said that the 31-year-old was "run over" by Spanish rider Jordi Torres after coming off.
Ducati rider Davies took a comfortable win ahead of Dutchman Michael van der Mark and England's Alex Lowes.
Rea, who won Saturday's race one, now leads the championship by two points from Marco Melandri.
Muir said Laverty had no initial feeling in his legs after the crash but that it had "come back".
"Torres ran straight over the middle of his back," Muir told Eurosport shortly after the race.
"He's taken a heavy whack. We think there is maybe pelvic and lower back injuries. He couldn't feel his feet at the time trackside but that has come back now so we can breathe a sigh of relief.
"He's taken a bad one there but the positive is that he's chatting to us now and on the way to hospital."
Laverty underwent surgery in Thailand on Sunday evening and must be in danger of missing at least one round of the series, with the riders back in action in Spain in three weeks.
However in a tweet, the 31-year-old insisted that his broken pelvis "won't keep me away for long".
"Thanks everyone for the encouraging messages. I had a successful operation last night in Buriram for some internal damage so we're on the road to recovery," said Laverty.
Rea appeared to suffer handling problems on his Kawasaki during Sunday's race as he went wide on a number of occasions, which included losing a lot of ground on lap five.