By Alan Baldwin
LONDON (Reuters) - Italian great Valentino Rossi goes into Sunday's MotoGP title decider in Valencia with his hopes of a 10th world championship hanging by a thread after a court ruled he must start in last place.
The 36-year-old, who has won seven of his titles in the top category and is battling against Yamaha team mate Jorge Lorenzo for another, had sought a stay of execution for the penalty pending an appeal hearing.
However, the Lausanne-based Court of Arbitration for Sport said in a statement it had dismissed Rossi's application and upheld a stewards' decision from last month's Malaysian Grand Prix.
"Valentino Rossi will commence the next (and last) event of the season...from the last grid position," it said.
The CAS added, though, that the arbitration procedure remained in progress and a final decision had yet to be made on the merits of the case.
Rossi leads Spanish rival Lorenzo by seven points, with 25 for a win, ahead of a finale that has been overshadowed by controversy since the last round in Malaysia.
The row kicked off, literally according to Rossi's accusers, when the Italian tangled with Honda's outgoing double world champion Marc Marquez at Sepang.
The young Spaniard has said Rossi used his leg to make him crash, an allegation the Italian has denied while suggesting Marquez was trying to sabotage his championship bid and help Lorenzo.
Race stewards allowed Rossi to keep his third-place result in Malaysia but handed him three penalty points which, added to an earlier one, triggered an automatic demotion for Valencia.
The sanction has divided the sport, fueled national rivalries and led to finger-pointing in both directions.
Italian Prime Minister Matteo Renzi called Rossi to express his support while Spanish counterpart Mariano Rajoy took to Twitter to back Marquez. Yamaha have taken up the cudgels against Honda.
Spanish media have compared Rossi's actions to those of Italian defender Mauro Tassotti who elbowed Spain's Luis Enrique in the face in an infamous incident in the quarter-finals of the 1994 soccer World Cup.
On the other side, Marquez filed a legal complaint after he and his family were allegedly insulted and physically attacked by Italian television reporters at their home near Barcelona.
Hundreds of thousands have also signed an online petition calling on MotoGP organizers to drop the Valencia penalty.
Such has been the atmosphere that the International Motorcycling Federation (FIM) and promoters DORNA canceled Thursday's pre-race news conference and summoned riders "to address the situation".
"The recent events ... have had a damaging effect on the staging of our competitions and poisoned the atmosphere around the sport," said FIM president Vito Ippolito.
"I express the hope that ... in Valencia the riders will fight it out on the track and in a way that fully respects the spirit of fair play."
(Editing by Kevin Liffey)