The Alfa-Romeo Tipo B was the most successful single-seater Grand Prix racing car of its time. Alfa-Romeo built and fielded it between 1932 and 1936. Initially as an Alfa-Romeo works car, then later under the Scuderia Ferrari label after Alfa took over its racing activities. Designed by legendary designer Vittorio Jano, the car was based on the no less legendary Alfa-Romeo 8C models. The P3 was Alfa-Romeo’s second single-seater after the Tipo-A monoposto of 1931.

The Marseille Grand Prix resulted in a sensational victory for Chiron in the Alfa Romeo monoposto. After an early battle with Borzacchini, Dreyfus, and Chiron, Nuvolari in the Maserati monoposto maintained the lead until his car broke down near the end of the race. This left the remaining race to be a duel between the Alfa Romeos of Chiron and Fagioli.

The 1933 Marseille Grand Prix was held on the Miramas oval course, which was located northwest of Marseille. Initially built for the 1924 Provence Grand Prix, it fell dormant after 1927. Only through the auspices of the A.C. de Marseille was the old course of Miramas reopened to racing in 1932. The 1933 race was the second Grand Prix of Marseille at Miramas. The flat 5.049 km oval track easily allowed speeds of up to 200 km/h, which made it one of the fastest events of 1933. The circuit had to be lapped 100 times for a total distance of 504.9 km.

The participation of drivers at Miramas was of the first class. Half of the entries had raced the preceding weekend at the Comminges GP. Among them was the victorious Fagioli, together with Wimille, Moll, von Waldthausen, Etancelin, and so on, all in Alfa Romeos. Maserati sent Zehender in the 3-liter monoposto, Nuvolari with a new works monoposto, and Borzacchini in a biposto. Chiron, who had joined Scuderia Ferrari recently, piloted an Alfa Romeo P3 monoposto. In addition, Ferrari Scuderia entered Fagioli, plus a third unnamed driver. The entry of Dreyfus in the big 4972 cc Type 54 Bugatti was completely unexpected. The Frenchman claimed to have got into the car the moment it was ready and drove it about 600 km over bad country roads from Molsheim to Marseille.

In view of the practice results, Nuvolari was three seconds faster than anybody else, including the highly acclaimed Alfa Romeo monopostos. On both practice days Nuvolari achieved an average speed of 208.9 km/h. The next fastest drivers were Borzacchini in the Maserati biposto and Moll in an Alfa Romeo Monza.

The Grand Prix started on the afternoon of August 27 at 3:00 pm, and 17 cars lined up on the starting grid. By the completion of the first lap Chiron was in front, trailed by Nuvolari and Borzacchini. On lap three, Nuvolari took the top spot but was soon overtaken by Chiron. On lap five, Nuvolari managed to grab the lead, followed by Chiron, Dreyfus and Fagioli. The spectators were thrilled to have witnessed a frantic battle for the lead. Then to their excitement, Dreyfus hustled into the front where he remained for three laps.

It was a race with the lead changing frequently. The leading group, which consisted of Dreyfus, Nuvolari, Chiron, Zehender, and Fagioli, was never separated by more than 100 meters apart. After 20 laps, for instance, Chiron was in front, shadowed by Nuvolari, and they had a five seconds advantage over Dreyfus, eight seconds over Fagioli and ten over Borzacchini.

After the first half of the race, Nuvolari was back in the lead and started to establish an advantage over the followers. On lap 70 Nuvolari led Fagioli by four seconds and Chiron by sixty-nine seconds. It appeared that Nuvolari would be the victor of the race. But his race ended abruptly on lap 80, when he got a broken rear axle hub. With his retirement, the battle between Maserati and Alfa Romeo was over, for both Chiron and Fagioli were racing in Alfa monopostos.

On lap 91 Chiron made a quick stop at his pits to have the left rear wheel changed in 24 seconds, which enabled him to keep first place ahead of Fagioli. Yet the Italian succeeded in passing Chiron to lead on lap 95. Both cars remained very close together until Fagioli had to stop for more fuel. Chiron won the race with an advantage of 70 seconds over Fagioli. This was his first victory with Alfa Romeo.