beat Arnoux to Turn One. He led after the first lap, with Arnoux ahead of de Angelis, de Cesaris, Alboreto, Derek Warwick, Rosberg (already up from twelfth) and Cheever. The two leaders quickly began to separate themselves from the rest, while a four-way nose-to-tail battle raged for fourth. On lap five, Cheever retired with ignition failure, de Angelis forfeited third place with a broken gearbox and Piercarlo Ghinzani abandoned his Osella in the pits with an overheating engine. Arnoux, after steadily closing the gap to Piquet, overtook the Brabham into Turn One and gained the lead on lap 10. Piquet let him through without a fight, knowing that the Ferrari was planning a fuel and tire stop, while he was not. When Rosberg finally got by de Cesaris for third at the end of lap 11, he was almost 15 seconds behind Piquet, but clearly faster. Alboreto, in fifth place and also threatening de Cesaris, had started on full tanks and, like Piquet, was not planning a pit stop. By lap 20, Rosberg had caught up with Piquet's Brabham and easily went by to take second, about twenty seconds behind Arnoux. On lap 29, the Ferrari's lead was up to almost 30 seconds when Arnoux came into the pits, as expected, followed soon after by Rosberg's Williams, whose intentions had been unclear. Arnoux rejoined after a stop of just 13.5 seconds, still barely in the lead; by the time Rosberg was able to get back on the track (his stop lasted 17.5 seconds), he was in fifth place behind Piquet, Alboreto and Jacques Laffite, none of whom had stopped. But just three laps after his pit stop, Arnoux suddenly coasted to a halt on the circuit with an electrical failure. When Laffite pitted, Piquet was back in the lead, with Alboreto up to second and Rosberg third, 25 seconds back. John Watson, having started in 21st position on the grid, was now in fourth, making his regular charge through an American Grand Prix field. It looked as if Nelson Piquet and Brabham-BMW were on their way to victory as Alboreto was doing all he could to stay close. Suddenly, on lap 51, Piquet slowed with a punctured left rear tire, and as he made his way back to the pits, Alboreto and Rosberg went by. While he was in the pits, Watson also came through. All that was left was