Marc Marquez says his chances of defending his MotoGP crown are effectively over after crashing out of the British Grand Prix in wet conditions.

Heading to Silverstone, the two-time reigning MotoGP World Champion was adamant he still had a shot at a third title with the points deficit at 52. But after his fourth retirement of the year, coupled with Valentino Rossi's victory, Marquez feels his MotoGP title fight has gone with the points gap expanding to 77 with six races to go.

"We lost the option for the championship but we will try to win as many races as possible from here to the end of the season," Marquez said. "No more thoughts on championship. I will try to win but when it is not possible I will try to finish in second place and on the podium. I will not change my level because I am already taking a lot of risks."

The Repsol Honda rider was acting as Rossi's main challenger in the first half of the race at Silverstone but had been struggling with a 'floating feeling' similar to the problems he'd suffered at the start of the year.

After managing the issue it eventually got the better of him at the start of lap 13 heading into Copse corner when the Honda RC213V slide out from underneath him and flicked him off.

"In the race I felt good and I was trying to follow Valentino and I was able to do it," he explained. "In some parts I was faster but in other points I had the character of the bike, that floating feeling in the rear, that we had at the beginning of the season.

"In rain I had that feeling which was difficult to manage during the race. I tried to manage it but in the end when I was behind Valentino I arrived at the end of the straight, I braked and lost the rear, the rear was locked. Just as I tried to save the crash I was already flying."