Metis Gilrera rider Marco Simoncelli has taken victory in the 250GP after Alvaro Bautista ran wide on the penultimate lap.
Marco Simoncelli is now second in the championship behind Mika Kallio.
Aspar Aprilia rider Alvaro Bautista led for the majority of the lap, occasionally swapping places with Simoncelli in second but eventually made a mistake on the penultimate lap to let Simoncelli through and take the lead at Bautista's home GP.
Britain's Eugene Laverty finished in 16th after battling with former 250GP world champion Manuel Poggiali, who eventually finished 14th.
250 championship leader Mika Kallio was forced to retire on lap 19 with a problem with his Red Bull KTM. Imre Toth also retired to the pits on his Team Toth Aprilia.
Hector Barbera finished third, but he was over 10 seconds behind the leading duo of Simoncelli and Bautista.
Polaris World Aprilia rider Mattia Pasini finished sixth and is third in the championship.
1 M. SIMONCELLI ITA Metis Gilera 41'01.859
2 A. BAUTISTA SPA Mapfre Aspar Team + 0.039
3 H. BARBERA SPA Team Toth Aprilia + 11.291
4 A. DEBON SPA Lotus Aprilia + 21.373
5 T. LUTHI SWI Emmi - Caffe Latte + 26.621
6 M. PASINI ITA Polaris World + 26.720
7 H. AOYAMA JPN Red Bull KTM 250 + 35.818
8 H. FAUBEL SPA Mapfre Aspar Team + 36.321
9 J. SIMON SPA Repsol KTM 250cc + 36.964
10 L. PESEK CZE Auto Kelly - CP + 41.237
11 R. WILAIROT THA Thai Honda PTT SAG + 52.391
12 Y. TAKAHASHI JPN JiR Team Scot 250 + 56.656
13 A. BALDOLINI ITA Matteoni Racing + 59.282
14 M. POGGIALI RSM Campetella Racing + 1'02.503
15 F. LAI ITA Campetella Racing + 1'02.656
16 E. LAVERTY IRL Blusens Aprilia + 1'07.418
17 R. GOMEZ SPA Blusens Aprilia 1 Lap
18 D. PRADITA INA Yamaha Pertamina Indonesia