Valentino Rossi's world title hopes were dealt a potentially fatal blow on Thursday when the Italian lost his appeal over being relegated to the back of the grid for Sunday's season-ending Valencia Grand Prix.
Rossi, already a seven-time premier category champion, was penalised for kicking defending champion Marc Marquez off his bike at the Malaysian Grand Prix last time out.
He appealed to the Court of Arbitration for Sport (CAS) who ruled Thursday that the sanction will stand.
Rossi leads Yamaha teammate Jorge Lorenzo by just seven points and therefore needs to finish in the top two to guarantee the title.
"Unfortunately starting from last is going to make everything a lot more difficult," said Rossi.
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"It was already difficult, but now it is much harder. We need to try to maintain our concentration and be competitive to get to Sunday's race in the best shape."
The clash between Marquez and Rossi has sparked an age old sporting rivalry between Spain and Italy with even the prime ministers of both countries intervening to back their compatriots.
Rossi is sure to face a hostile atmosphere in Valencia with the race unusually for MotoGP being declared as high risk by the authorities for fears fans of the riders could clash.
"My dream was to fight for the championship in a clean way," added Rossi.
"The season has been a very good one and I am still in position to fight for the title. This decision doesn't change the passion I have going forward."
The fallout from the incident escalated last weekend when two Italian journalists tried to enter the grounds of Marquez's Catalan home.
Marquez's representatives released a statement saying the journalists had been reported to the police for assaulting and insulting the 22-year-old rider and his family.
However, the reporters replied claiming their cameras had been broken in the scuffle, whilst their TV company said they would pursue the Marquez family for "assault, slander and theft."
"It has been a tough week," Marquez admitted on Thursday.
"I have tried to prepare for this Grand Prix like any other, but it hasn't been possible.
"I don't expect an apology from Valentino. I understand perfectly that Valentino has a championship in play.
"In the end I don't want to be caught in the middle, although every one races their own race and fights for their own result."
The bad blood between Marquez and Rossi has meant Lorenzo has gone under the radar as he aims for his third world title.
However, he did manage to anger his own team when his attempt to have his lawyers present at Rossi's appeal hearing was rejected by CAS.
Despite his less than friendly rivalry with Rossi, though, Lorenzo insisted he will remain with Yamaha.
"I have a contract and my intention is to continue with Yamaha not just as a rider, but also after I retire.
"All marriages do through difficult times and Valentino and I form one of the best teams in the world."
