MotoGP points leader Valentino Rossi insists four riders are firmly in the 2015 title fight, while rejecting any suggestion of a 'crisis' for reigning champion Marc Marquez.

Rossi retained his 15-point advantage by finishing second in Sunday's French MotoGP, round five of 18, but with Yamaha team-mate and race winner Jorge Lorenzo replacing Andrea Dovizioso as his nearest rival.

Meanwhile reigning double champion Marquez - winner of the opening ten races of last year - is now 33 points behind after dropping from pole to fourth. The Repsol Honda star later explained that the race day heat caused front-end problems for the RCV riders.

"Marc is a little bit behind in the championship also because he doesn't have the 20 points from Argentina [when he fell in their penultimate lap clash]. And after the first three races I heard also that Jorge was in crisis and now he won two races in a row," said Rossi.

"This can happen also to Marc because he is a double world champion. He is a rider with an incredible amount of talent so he can arrive at Mugello and win without any surprise."

Lorenzo had failed to finish on the podium in the opening three rounds before winning the next two races, propelling him up the championship order.

"I was very far from Valentino before Jerez," Lorenzo confirmed. "Some people said I was in crisis and probably some of them are going to say that Marquez is in crisis because of these races.

"But you know myself, Marc, Valentino, we have the talent and we have to wait for all the circumstances to be on the right way and Marc is going to come back. He is going to win races and be competitive in the future. Obviously we have to try to keep this points advantage.

"The Honda I think is the same or maybe a little bit better than last year, but luckily for us we improve the braking and entry for the corners and can keep our strong points, corner speed and acceleration."

Dovizioso, third at Le Mans, believes Marquez's talent is masking problems with the Honda.

"It is always difficult to understand details if you are not on the bike, but my opinion is that the talent of Marc hides some limit of the Honda. Because he is the only one who is able to go fast. Also last year and especially this year," the Italian said. "So I believe Honda at this moment does not have a perfect balance."

Unlike Rossi (2), Lorenzo (2) and Marquez (1), Dovizioso is yet to win a race in 2015, but with four podiums from five events Rossi is adamant the Ducati rider is in title contention.

"I think that the [championship] balance will change week by week and I think all four names [Rossi, Lorenzo, Dovizioso and Marquez] are fighting for the championship. Also Dovi because he is very fast, very constant," said Rossi, who has led the standings since victory in the Qatar season opener.

The Doctor also picked Dovizioso out as a favourite for the forthcoming Italian round: "In Mugello they [Ducati] go for a test, make a good lap time, work very hard. So I think that also Ducati will be there."

But Rossi confessed that at present Lorenzo is his biggest threat for a tenth world title.

"In this moment I think Jorge is the rider more in shape, more dangerous, more difficult to beat."