MotoGP season finale: Who will be champion in Valencia?

Jorge Lorenzo (left) and Valentino Rossi (centre) will vie for the title on Sunday, but will Marc Marquez (right) have a role to play?

Accusations of cheating, claims of 'poisoning' the sport, interventions from prime ministers across Europe - it has all got very ugly before the conclusion of the MotoGP season in Valencia this weekend.

In one corner, a legend of the sport - nine-time world champion Valentino Rossi, a darling across the world and arguably the most popular motorbike rider of all time.

In the other, his Yamaha team-mate Jorge Lorenzo, looking for a third title in five years.

And the third man in the mix? Reigning champion Marc Marquez.

Rossi will have to start from the back of the grid in Valencia - does that make it mission impossible?

Who needs what to win the title?

Only two men can be crowned world champion in Valencia on Sunday.

Rossi, 36, is a seven-time MotoGP champion but has not won the championship since 2009. He will be the oldest 500cc/MotoGP champion since Les Graham in 1949 if he takes the title.

Yamaha team-mate Lorenzo, 28, won the title in 2010 and 2012 and is seven points behind Rossi going into the final race.

If Lorenzo wins, Rossi must finish second to deny him a third title. Tricky, as he will have to start from last place.

Rossi may take comfort from the fact that Marquez did win from last on the grid in Valencia in 2012 - albeit on a Moto2 bike.

How did it come to this?

An exciting on-track battle had been building all season, with Rossi holding a slender advantage over team-mate Lorenzo heading into the penultimate race in Malaysia last month.

A routine pre-race news conference was ignited when Rossi accused Marquez - sitting just a few feet away - of attempting to disrupt his races and wanting Lorenzo to win the title.

Marquez, champion in 2013 and 2014 and a childhood fan of Rossi, denies the claim but did then clash with the veteran in Malaysia.

Trouble in Sepang

Marquez overtook Rossi on lap 13 with a bold move before the Italian forced his way back up the inside. Both riders went wide, and after slowing down and looking at each other, the two touched.

Marquez was knocked from his Repsol Honda, and Rossi carried on to finish third.

Race stewards blamed Rossi for the crash and decided, following a post-race investigation, he would start the final race of the season from the back of the grid.

Rossi (left) and Marquez (right) clashed in Malaysia, with Marquez coming off his bike

He later accused Marquez of "making me lose the championship".

Rossi appealed to the Court of Arbitration for Sport and asked for his penalty to be suspended. Lorenzo asked to participate in the appeal but was denied the chance.

On Thursday, Cas refused to suspend the penalty - Rossi will not be allowed to qualify for Sunday's race as normal, and the prospect of a messy courtroom battle deciding who would be champion seems to have dissipated.

Thankfully the championship will be decided on the track.

'Sport needs to win'

The clash between Rossi and Marquez led to heated discussion in both Spain and Italy.

Italian Prime Minister Matteo Renzi called Rossi to express his support while Spanish counterpart Mariano Rajoy used Twitter to back Marquez.

The Spanish media 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 World Cup.

Marquez, meanwhile, filed a legal complaint alleging he and his family were insulted and physically attacked by Italian television reporters at their home near Barcelona.

Vito Ippolito, president of the International Motorcycling Federation, said the clash was "damaging" and "poisoned the atmosphere around the sport".

No wonder the organisers of MotoGP released a statement on Thursday reminding the riders that "sport needs to win".

What do the riders have to say?

"This situation doesn't modify my passion or my thinking for the future" - Rossi faces the media

In packed news conferences in Valencia on Thursday, all three protagonists spoke to the media.

Rossi accepted his starting position "makes everything difficult", but said the incident has not dampened his passion and he will continue racing until at least the end of next season.

Team-mate Lorenzo played down talk of a Yamaha rift, saying he wanted to continue with the team "forever".

"Naturally all marriages have some moments of disagreement but our relationship in the future will be the same," said the Spaniard.

Compatriot Marquez, who has already secured third place in the championship, accepted the fall-out from Sepang had resulted in "one of the most difficult weeks of my life".

He added: "I try to forget and concentrate to prepare for the last race and it wasn't possible to prepare in a normal way."

A British champion at last!

Danny Kent is the new Moto3 world champion

Somewhat buried in the Rossi-Lorenzo-Marquez clash was the fact Britain has a new world champion.

Danny Kent, 21, became the first Briton to win a grand prix world championship in any class since the late Barry Sheene won the 500cc title in 1977 by winning the Moto3 class.