The Formula Atlantic session saw a couple of problems: a manhole cover was lifted, and the track surface at turn 9 at the end of the back straight (Washington Street) had begun to break up in the same way Detroit and Dallas had done in the past.

It was the same four pre-qualifiers as at the last event in Mexico, albeit in a different order, as Alex Caffi took second in the Dallara, Stefan Johansson was third in the Onyx, and Brundle's Brabham team-mate Stefano Modena was fourth.

Senna's Friday time of 1:30.710 stood up through the second session and gave him his 34th career pole position, breaking Jim Clark's record of 33 which he had equalled in the previous race in Mexico.

The only American driver in the field, Phoenix native Eddie Cheever, qualified his Arrows-Ford in 17th place, some 3.1 seconds slower than pole man Senna.

Nannini ran third followed by Nigel Mansell, Alex Caffi, Stefano Modena, Martin Brundle, Gerhard Berger, Andrea de Cesaris and Michele Alboreto.

Despite Senna's seemingly commanding position, Prost remained confident of winning as he had seen that his McLaren was handling better than his teammate's.

A stop for new tires, after being passed by Berger (whose palms were still raw and sore from his Imola crash only six weeks before), dropped him back two more spots to fifth.

Berger's Ferrari suffered alternator failure (meaning no power to the revolutionary semi-automatic transmission) 9 laps after Caffi's retirement.

Stefan Johansson had managed to drag the Onyx not only through pre-qualifying but also onto the grid and drove a steady race to be running in 7th place just outside the points before having to retire on lap 50 with suspension damage from a previous puncture.

As was predicted, the two-hour time limit was reached after 75 of the scheduled 81 laps, and Prost coasted to his only United States win (after not having won at Watkins Glen, Long Beach, Las Vegas, Detroit or Dallas), and increased his then all-time record victory total to 36 and his first win in a naturally aspirated car (his only other season in F1 without turbo power had been his rookie season with McLaren in 1980 when the team used the Cosworth DFV V8 engine).

After struggling through practice, qualifying and warm up, and starting from 14th spot, Patrese and technical director Patrick Head had guessed at a setup and finally got it right for the race.

Ken Tyrrell was the only team boss who refused to sign the document which would have allowed the race length to be reduced.