Only three works teams contested the Belgian Grand Prix. Alfa Romeo entered Farina, Fangio and Consalvo Sanesi in their 159 supercharged machines. Ferrari fielded Alberto Ascari, Luigi Villoresi and Piero Taruffi in 375F1s. Talbot-Lago completed the field with seven cars: Louis Chiron, Philippe Étancelin, Louis Rosier, Yves Giraud-Cabantous, Pierre Levegh, Johnny Claes and André Pilette. The Maserati entries of Prince Bira and José Froilán González, though registered, did not start due to the cars being unready. Thirteen cars took the grid.
Juan Manuel Fangio claimed pole position at an average lap speed of 191.819 kilometres per hour, placing Farina second and Luigi Villoresi's Ferrari third on the grid. Ascari and Taruffi shared the second row; Sanesi's Alfa Romeo and Rosier's Talbot, the quickest of the French cars, made up row three.
Villoresi led at the start, his Ferrari two seconds ahead of Farina by the end of the first lap and building further over Ascari and Fangio through the opening exchanges. Farina worked through to the front by lap 3 and a genuine battle established itself between the Alfa and the two Ferraris.
Fangio moved through the field methodically. He passed Villoresi for third on lap 5 and was ahead of Ascari and running second to Farina by lap 6. Villoresi was forced into the pits with an oil leak on lap 9 and Taruffi's 375F1 broke its rear axle, ending his race. On lap 10 Fangio set the fastest lap of the race.
The pit-stop phase changed the outcome. Farina came in on lap 14 for fuel and rear tyres; Fangio inherited the lead and pitted in turn at the end of lap 15 for the same service. What followed became one of the most consequential mechanical failures in the early championship era. After refuelling, Alfa Romeo's mechanics could not remove the left rear wheel from its hub. Rather than strip the wheel entirely, they changed the tyre on the rim itself. Fangio sat in the stationary car for more than fourteen minutes before rejoining the circuit, emerging in tenth place. The Belgian crowd rose to applaud him as he drove back out.
Farina, now back in the lead and serviced, drove the second half of the race with increasing comfort. Ascari's brakes faded through the closing stages, costing time to the growing gap behind Farina. Chiron's Talbot retired on lap 28 with ignition trouble after having already stopped once in the opening laps for spark plugs. Sanesi's Alfa Romeo retired earlier with a radiator failure.
Farina won in a time of 2 hours, 45 minutes and 46.2 seconds at an average speed of 183.988 kilometres per hour, nearly three minutes clear of Ascari's Ferrari in second. Villoresi came home third, ninety seconds behind Ascari, for his first Formula One World Championship podium finish. Rosier's Talbot-Lago finished fourth, two laps adrift of the leaders. Giraud-Cabantous completed the top five in a second Talbot-Lago, also two laps down. André Pilette and Johnny Claes took sixth and seventh in two further Talbot-Lagos. Fangio crossed the line ninth, four laps behind the winner, salvaging a single point for the fastest lap he had set on lap 10.
The result put Farina on twelve championship points and placed him first in the Drivers' Championship standings. Fangio held ten points, Lee Wallard nine from his Indianapolis 500 win, and Ascari six after his second place at Spa.
Spa also provided an early indication that Ferrari could match Alfa Romeo across a full race weekend, with Ascari and Villoresi consistently competitive from the front of the grid. A month later at Silverstone, on a circuit better suited to the Ferrari's characteristics, the balance between the two teams would shift further. The Belgian Grand Prix holds statistical significance in Fangio's career: it was the only race he started in the Formula One World Championship — excluding retirements — in which he finished outside the top four.