MISANO ADRIATICO, Italy, Sept 19 (Reuters) - Ducati"s Francesco Bagnaia survived a late charge from world championship leader Fabio Quartararo to win the San Marino Grand Prix on Sunday and claim a second straight MotoGP victory. Pole-sitter Bagnaia led by 2.7 seconds at one stage before Quartararo closed the gap in the final laps, cutting the Italian"s advantage to two-tenths of a second. Rookie Enea Bastianini of Avintia Ducati enjoyed a superb race to secure a debut podium finish after starting 12th on the grid. Repsol Honda"s Marc Marquez finished fourth. Quartararo, who initially struggled to keep pace with the Ducatis of Bagnaia and Jack Miller, overtook the Australian into second place with 14 laps to go but failed to go past Bagnaia, who also won in Aragon last week. A fading Miller finished fifth. "I knew that with the soft rear tyre, I was a struggling a bit and I tried to push in the first few laps to open the gap," Bagnaia said. "The last 10 laps when Fabio was recovering were very difficult... he was a bit better in the last part but we were incredible today. "Two victories in a row is incredible for me. I was struggling to win my first race... there was something missing. Now I"m very happy." Quartararo said he had given it his all. "There were a few moments where I closed the gap, but Pecco (Bagnaia) was on another level today... but we did the job today because we still have a good lead in the championship," he said. The Frenchman holds a 48-point lead over Bagnaia with four rounds to go. Former world champion Valentino Rossi finished a disappointing 17th for Petronas Yamaha and reigning world champion Joan Mir of Spain came sixth on his Suzuki.