Twenty-three-year-old Lotus rookie Emerson Fittipaldi captured his first Grand Prix win in only the fourth start of his Formula One career. The dominating performance of Jackie Stewart's brand new Tyrrell went by the boards when his engine failed, and the Brazilian inherited the lead with eight laps to go when Mexican Pedro Rodríguez had to stop for a splash of fuel. Fittipaldi came home thirty-six seconds ahead of Rodriguez, while his Lotus teammate Reine Wisell finished third in his Formula One debut.
Jochen Rindt, whose first career victory came at Watkins Glen in 1969, took charge of the 1970 Driver's Championship with five wins, including four in a row at mid-season in the revolutionary Lotus 72. When Rindt was killed during practice for the Italian Grand Prix, the team was devastated, and they withdrew from that race and the next one in Canada. With two new drivers for the last two races of the season, the team were determined to clinch a posthumous title for their late team leader.
Though the Ferrari of Jacky Ickx was fastest in the initial practice session on Friday with a time of 1:03.07, all eyes were on the Tyrrell 001 of Jackie Stewart, which had nearly won in its first outing in the previous race in Canada. The final session on Saturday was marred by a downpour that left only fifteen minutes of dry track time, and it was not enough for Stewart to knock Ickx off the pole. Fittipaldi, who spent the first half of the season in European Formula Two, was just five hundredths behind Stewart in third.
On Sunday, with a crowd exceeding 100,000 for the second straight year, black clouds and a brief sprinkle 20 minutes prior to the race caused a lot of excitement among the crews on the grid, as many teams changed to rain tires and back again. By the start, however, all but Clay Regazzoni and Derek Bell had reverted to slicks. Stewart took the lead off the grid, ahead of Rodriguez, as Fittipaldi erred on the side of caution and dropped to eighth behind Ickx, Regazzoni, Chris Amon, John Surtees and Jackie Oliver.
By lap 17, the Ferraris of Ickx and Regazzoni had moved by Rodriguez, but by that time, Stewart's lead was nearly twenty seconds. Graham Hill, in a privately-entered Lotus 72, came into the pits on lap 30 with fuel sloshing around in the cockpit, as a fitting had come loose under the seat. The team took 10 minutes to fix the leak, threw some water on Hill, whose overalls were soaked in fuel, and sent him back out. Several laps later, Hill returned to request they find him some dry overalls, as the gasoline was burning his skin. When he stopped again to change clothes, the team said they had not been able to locate any new ones. Hill, however, saw John Surtees, who had retired on the seventh lap, sitting on the wall, and promptly stripped him of his overalls and undergarments. The two former World Champions were naked in the pits as Hill was doused with water before donning Surtees' clean clothes and returning to the track, only to retire on lap 72 with a broken clutch.
At half-distance, Stewart was in a class by himself, nearly half a lap ahead of Ickx, with Rodriguez in third and Fittipaldi about to be lapped in fourth. Ickx suddenly pitted on lap 57 to repair a broken fuel line, and he rejoined in twelfth place. A heroic drive back up the charts, including the race's fastest lap just three laps from the finish, would earn him a well-deserved fourth place.
On lap 76, with a one-minute cushion, the leading Tyrrell began trailing smoke from the left-hand exhaust pipe. The smoke slowly grew worse, as Rodriguez tore into Stewart's lead, taking off five seconds a lap, and the Lotus teammates unlapped themselves. On lap 83, with its oil gone, the Cosworth engine in the Tyrrell seized, leaving Rodriguez with an 18.8 second lead over Fittipaldi, who led Wisell by another 46 seconds.
The BRM crew were nervously pacing up and down in the pits, hoping the thirsty engine could go the distance without stopping. At the end of his 100th lap, however, Rodriguez coasted into the pit lane with a dry tank. BRM quickly poured in a few gallons of fuel, as Fittipaldi crossed the line, leading the richest race of the year. Rodriguez rejoined ahead of the second Lotus of Wisell, but he had lost 38 seconds to Fittipaldi and could do nothing about the Brazilian's lead.
Years later, Fittipaldi would remember:
"I took the lead and, going over the finish line, I saw for the first time Colin [Chapman] jumping and throwing his hat, something I'd seen him do for Jim Clark and Graham Hill and Jochen, and I kept saying to myself, 'He's doing that for me. I won the race. I won the US Grand Prix!' It was unbelievable."
His victory was the seventh American win for Lotus, and it clinched the Driver's Championship for the team's fallen leader, Jochen Rindt, and the Constructor's Championship for Lotus and Colin Chapman.
- The following winter, for the second time, the Watkins Glen Grand Prix Corporation was honored by the Grand Prix Drivers Association with the "Best Organized Race Award," shared this time with the German Grand Prix at Hockenheim.
- This was the final year in which the Grand Prix was held on the 2.35 mile layout of the track. Watkins Glen International underwent extensive revisions over the course of 1971, and by that year's race, the track had been lengthened to 3.377 miles. An interim layout was adopted for the Six Hours, as the new section on the exit of the Loop-Chute had not been completed.