Marc Marquez wins thrilling San Marino GP as Valentino Rossi blows it

San Marino: Honda`s world champion Marc Marquez of Spain won an enthralling San Marino MotoGP on Sunday as Yamaha`s Valentino Rossi blew his chances with tactical errors and teammate Jorge Lorenzo crashed out.

Marquez`s move to switch to slick tyres on a drying Misano circuit after rain led to his fourth win of the season in front of British duo Bradley Smith (Yamaha) and Scott Redding (Honda).

"The bike was moving about and I thought it was time to change as the track was drying out and it was new asphalt," said Marquez.

"It`s nice to be here again on the podium and victory was our target so I`m very happy," added the Spaniard who becomes the first Honda rider to win at San Marino since compatriot Dani Pedrosa in 2010. 

Championship leader Rossi`s army of home fans looked on in bewilderment as the nine-time world champion failed to make the switch from wet tyres to slicks with seven laps to go, when he was in the lead, handing the race to Marquez. 

The `Doctor` eventually settled for fifth place but it was still a successful day as Lorenzo`s crash meant Rossi extended his championship lead to 23 points over his Yamaha teammate with Marquez now 63pts back with five races to go.

"It`s true that the championship is a lot more important than winning this race, it`s the main target," said Rossi.

"Unfortunately Jorge crashed and I was able to gain another 11points. This is good for the championship, but it`s a shame to miss out on the podium, because I wanted to arrive in the top three in front of all the spectators."

Redding rode a remarkable race after dumping his bike in the dirt only to get back up and finish third, the first time two British riders had finished on the podium since 1979. 

Smith, 24, who made the brave decision to stay on slick tyres for much of the race was rewarded with his best ever result in MotoGP. 

"I went one lap, then two laps (on slicks) but I just kept saying `luck favours the brave, luck favours the brave, luck favours the brave` and all the others were making two pit stops but I never expected to be on the podium," said the Oxford rider whose best previous finish in the highest category was third in Australia in 2014. 

Lorenzo took the early lead with Marquez and Rossi in hot pursuit but just minutes into the race rain began to fall on the freshly laid new track which forced the field to scramble for a switch of bikes and wet tyres. 

The leading trio pitted together and swiftly hopped onto new bikes but it was Marquez who took advantage and went into the lead as they came back out with 20 laps to go. 

With 15 laps to race and the track drying out, Lorenzo and Rossi blew past Marquez as the Spaniard inexplicably looked behind him, much to the delight of the fans who went wild at the sight of the Italian moving into contention for back-to-back wins for the first time since 2009. 

The two Yamahas then began to pull away from Marquez but Rossi again turned the race upside down with a daring overtake with 12 laps to go as he took the outright lead for the first time. 

However, Rossi stayed out on the track too long and with Marquez on faster tyres, he quickly caught the Italian when the Yamaha rider finally came into the pits and relinquished the lead for good. 

Johann Zarco won the Moto2 race, extending his lead in the championship, with Enea Bastianini winning the Moto3 event.