The 45th International 500-Mile Sweepstakes was held at the Indianapolis Motor Speedway in Speedway, Indiana on Tuesday, May 30, 1961. For the first time since 1949, the Indianapolis 500 was not recognized on the World Championship calendar. The race celebrated the 50th anniversary of the first Indy 500 in 1911.

Eddie Sachs and A. J. Foyt were battling for 1st-2nd in the latter stages of the race. On Foyt's final scheduled pit stop, his crew was unable to properly engage the fuel mechanism, and his car did not take on a full load of fuel. Foyt returned to the track, and was pulling away from Sachs. Foyt's car was running faster due to the light fuel load, but his crew signaled him that he would be unable to make it to the finish without another pit stop. The crew borrowed a fuel feed mechanism from Len Sutton's team, and signaled Foyt to the pits.

Foyt gave up the lead on lap 184 for a splash-and-go. That handed the lead to Sachs, who was now leading by 25 seconds. With three laps to go, the warning tread showed on Sachs' rear tire and Sachs decided to play it safe. Rather than nurse the car around, he pitted to replace the worn tire on lap 197. Foyt took the lead with three laps to go and won his first (of four) Indy 500 victories by a margin of 8.28 seconds.

A notable story included the appearance of two-time defending Formula One World Champion Jack Brabham from Australia, who drove the race in a low-slung, British built Cooper powered by a Coventry Climax engine. Dubbed the "British Invasion," it would be the first notable post-war appearance of a rear-engined car, and within five years the rear-engined revolution would take over the Speedway. The venerable front-engined roadsters with their larger and more powerful engines were much faster down the long straights, but the superior handling of Brabham's Cooper in the corners kept his car competitive. Brabham qualified 17th at 145.144 mp/h and drove the car to a respectable 9th-place finish, completing all 200 laps. He had planned to run conservatively and make only two pit stops, but tire wear and fuel consumption forced him to make a 3rd stop, negating his strategy. Had he driven more aggressively with three pit stops, he might have been much closer to the lead serial.

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