With five races to go in the 2010 motoGP season, championship leader Jorge Lorenzo had a large lead, but was slowly being reeled in by compatriot Dani Pedrosa.
After the Aragonese race, the gap was 56 points, or the equivalent of just over two race victories.
However, Lorenzo was practically crowned champion after Pedrosa crashed out of the Friday practice session in Japan.
Repsol-Honda rider Pedrosa suffered a double fracture in his left collarbone after six minutes at the road course at Motogi circuit, falling at turn nine after beginning to brake for the corner.
It was reported by the team that the problem was caused by "a small problem with the throttle cable [that] didn't allow Pedrosa to close the throttle when he came to brake, an issue which has already been investigated and resolved."
Pedrosa will miss the race on Sunday, as well as the races at Sepang in Malaysia and Phillip Island in Australia, but may return for the final races of the season.
It was going to be very difficult for Pedrosa to overthrow a 56-point gap, but that will now be impossible as he will only compete for a maximum of two more races at the end of this season.
The next contender, Australian rider Casey Stoner, is 129 points behind Lorenzo, a gap which cannot be overturned with five races remaining.
If Stoner won the remainder of the races and Lorenzo picked up no points, the Yamaha rider would still finish four points ahead of the Ducati.
If Pedrosa returned and won his final two races, with Lorenzo picking up no points, Lorenzo would be six points ahead of Pedrosa.
Lorenzo has been the most consistent rider this season, finishing every race and only finishing off the podium once. He gained the most from Rossi's leg break earlier this year.
The other action on Friday saw Valentino Rossi top the time sheets, over 0.20 ahead of his nearest challenger Dovizioso and exactly 0.30 faster than teammate Jorge Lorenzo.
Stoner and Spies were fourth and fifth, followed by Aoyama, Edwards, Barbera, Capirossi, and Simoncelli.
The riders who finished outside the top 10 at the end of the practice session were Melandri, Bautista, Hayden, de Puniet, and Espargaro.