Sepang, Malaysia (AFP) - Ducati's Andrea Dovizioso won a dramatic and damp Malaysian MotoGP Grand Prix on Sunday (Oct 30) to keep his world title hopes afloat after championship leader Marc Marquez of Spain finished fourth.

"Yes, I am happy to keep my championship challenge alive," he said at the trackside.

The Italian adopted a cool strategy and worked hard to stay in the front pack as a downpour just before the start left standing water on much of the Sepang circuit.

Dovizioso, who now has six wins this season, quickly defused speculation that team-mate Jorge Lorenzo had been under orders to let him through at Turn 15 when the Spaniard was in the lead.

"He lost the front. I (also) lost the front many times," he said.

Dovizioso, who started on the front row, crossed the line in 44min 51.497sec.

Lorenzo was 0.743sec slower while Frenchman Johann Zarco was third at 45:01.236.

Lorenzo said he pushed hard for victory but lost his grip in lap 15 when he tried to break.

When asked if there had been any team instructions to let Dovizioso win, Lorenzo told reporters: "Honestly, I did not see anything. In the rain, you cannot lose any concentration.

"I wanted to win the race but was not prepared to do something crazy. I lost grip in the front in Turn 15. I thought I was going to crash. I did not want to crash into Dovizioso."

It was the first time this year that the Ducati riders had achieved a 1-2 finish.

Dovizioso, who has a slim mathematical chance of claiming the title at Valencia in two weeks, said the whole team worked perfectly.

"We did everything perfect and it wasn't easy. So I am so happy about that, to show to everybody that with our work we can really be competitive in this difficult track in the dry and wet," he said.

The 31-year-old won in Malaysia last year in similar wet conditions. But Dovizioso admitted that Marquez would be competitive in Valencia, adding that it would not be a surprise if he wins the title there.

"What Marquez did this season is incredible," he said.

Marquez, 24, can lose the championship if Dovizioso wins in Valencia and he himself finishes outside the top 11.

Zarco rode a brilliant race and set an electric pace to lead most of the way.

He said he enjoyed riding fast at Sepang and was glad to secure a podium finish.

"It is okay (that) Lorenzo and Dovizioso overtook me. They are much better riders," Zarco said.

"I am happy with a third position. We had a good day. I am highly motivated for the season-ending race in Valencia."

Marquez, who started from the third row on a Honda, was under intense pressure to wrap up the championship battle in Malaysia.

He quickly moved up to third in a fast-riding pack led by Zarco but could not maintain his pace on the wet track.

Dani Pedrosa, who started on pole, finished fifth for Honda ahead of Danilo Petrucci.

Italian legend Valentino Rossi finished seventh on his Yamaha.

The riders will meet in Valencia on Nov 12 for the final showdown, with Marquez leading Dovizioso by 21 points.