(CNN) -- Jorge Lorenzo kept the MotoGP title race alive with victory at the Indianapolis Grand Prix on Sunday as world champion Valentino Rossi crashed out.
Valentino Rossi ploughed into the grass alongside the Indianapolis circuit when he crashed out.
Rossi saw his lead halved to 25 points with five races remaining as the Italian failed to finish for the first time since 2007.
He went down on lap nine of 28 when battling for the lead with Yamaha teammate Lorenzo, and was able to remount -- but then had to retire two laps later due to his damaged motorcycle.
Lorenzo had started the American race from second on the grid, ahead of Rossi but behind his fellow Spaniard Dani Pedrosa.
Pedrosa, who won at Laguna Seca in California earlier this year and is fourth overall, suffered a crash on just the fourth lap while still leading.
He picked up his Repsol Honda machine and rejoined the race in last place, but could only finish 10th.
Lorenzo cruised to victory more than nine seconds clear of Alex de Angelis, who earned his first podium finish after starting fourth on the grid for San Carlo Honda Gresini.
The 22-year-old now has 187 points, behind eight-time world champion Rossi's 212.
"Before this race I was telling the press that it was almost impossible, whereas now I would say it is difficult, but not impossible," Lorenzo told the MotoGP Web site of his title chances.
He was delighted after having himself failed to finish the last two races at Brno and Donington.
"Today the situation has changed completely and now it has happened to Valentino and Dani, unfortunately for them. However, for me, the situation is good," Lorenzo said.
"It was difficult to keep my concentration for 20 laps, because it was a little bit boring. Bit you cannot relax when it is like that because if you think about something else you could crash. Anyway, I had some fun on the last lap and it is a very nice feeling!"
Former world champion Nicky Hayden finished third in his best result since joining Ducati, with the American having finished second in the inaugural Indianapolis event last year before switching teams.
He managed to hold off a late challenge from Andrea Dovizioso, his replacement at Repsol Honda, while American Colin Edwards came home in fifth on his Monster Yamaha Tech 3.
British rider James Toseland equaled his best finish in MotoGP when he claimed sixth for Edwards' team after Italian Marco Melandri crashed late on.