Ferrari did not bother to send its cars to the United States as none of the drivers were in the running for the World Championship and so it was down to BRM, Lotus, Lola, Cooper and Porsche to scrap over the event. Graham Hill was in a strong position in the World Championship and so his rival Jim Clark had to aim for victory. Jack Brabham arrived with a revised version of his own BT3 while the field was bolstered by a number of local drivers with Tim Mayer in a third factory Cooper, Roger Penske in a Lotus 24, Jim Hall in Brabham's old Lotus and Bob Schroeder in one of Rob Walker's cars which had been rented to US entrant John Mecom.

Clark set the pace in qualifying with Richie Ginther second fastest in his BRM, just a tenth faster than Graham Hill. Dan Gurney was fourth fastest in his Porsche and then came Brabham in the Brabham and McLaren's Cooper. John Surtees was down at the back of the grid after his Lola suffered a steering arm failure and he crashed heavily. Surtees took over Roy Salvadori's car for the race.

At the start Clark took the lead with Hill beating Ginther away. Brabham grabbed fourth ahead of Gurney and McLaren, although Gurney was soon able to get his Porsche past the Brabham. He also managed to get ahead of Ginther to run third. On lap 12 Hill took the lead but Clark fought back and moved ahead again on lap 19. Further back the Gurney-Ginther battle for third continued until Ginther went out with engine trouble on lap 35. Gurney then came under pressure from McLaren and fell behind the Cooper on lap 57. In the closing stages Gurney also fell victim to Brabham. The result meant that Hill and Clark would go to South Africa in December with the World Championship still open and if Clark won with Hill second the Lotus driver would snatch the title with equal points but four wins to Hill's three.