Competitors were divided into four classes based on engine capacity. Class I were the up to 1100cc cyclecars, Class II was for cars up to 1500cc, Class III for cars up to 2000cc, and Class IV for cars over 2000cc.[1]
Cars started the race individually in order of race number, with a three minute interval between each car starting with class II, then class III, class IV and finally the class I competitors who only needed to complete 3 laps.[1]
During his first lap, 2-time Targa Florio winner Giulio Masetti's Delage overturned, severely injuring him. He died shortly afterwards.[1]
The main race was dominated by Meo Costantini's Bugatti, who lead from the start and never lost the lead, setting a fastest lap of 1 hour and 26 minutes on his fifth and final lap. Behind him, fellow factory Bugatti driver Ferdinando Minoia drove to a mostly unchallenged second place. Behind them the race was much closer. After the first lap, third to eighth place were separated by less than two minutes, with Emilio Materassi's Itala Special in third followed by Wagner, Dubonnet, Divo, Goux and Maserati. Dubonnet and Goux charged up the order on the second lap, moving up to third and fourth places respectively, making it a Bugatti 1-2-3-4, while Materassi dropped to sixth due to a pit stop. By the end of lap three, Materassi had pushed back up to third place, while Dubonnet had dropped to seventh as he made a pitstop.[1]
Factory Delage drivers Divo and Benoist would then retire, mourning the loss of teammate Masetti. Goux was able to pass Materassi on the fourth lap, giving the Bugatti factory team a 1-2-3 which they would hold until the end, with Materassi finishing fourth, while Dubonnet was fifth, and first in Class II. After setbacks which dropped him as low as 12th, Maserati finished 8th and won Class III.[1]
