Jorge Lorenzo denied that he backed off intentionally at Motegi, saying he was simply unable to match Dani Pedrosa's pace.
The Yamaha rider had set a new record en route to pole on Saturday in Japan and had then led the opening 11 laps of the race, but was unable to establish any sort of gap over Pedrosa.
When the latter made his move down into Turn 5 Lorenzo initially tried to respond, but within two laps he was already one second behind and fell away gradually over the remaining laps.
The same pattern had been set at the preceding Aragon Grand Prix, although Lorenzo insisted it was not thoughts of needing only second places to secure the 2012 crown that had caused him to drop back.
"I was completely at the maximum trying to stay with Dani, but today it was impossible," he explained. "On the straight there was too much difference, and he was riding well.
"In the beginning I tried to open a gap but I couldn't, the maximum difference was just four tenths of a second. Then when Dani came by I tried the maximum to follow but I just couldn't.
"For sure the championship is more close [as a result], but we will see what happens at another track."