United States GP: Andrea de Cesaris, Dallara BMS-190 Ford, leads Nelson Piquet, Benetton B189B Ford, Gerhard Berger, McLaren MP4-5B Honda, Thierry Boutsen, Williams FW13B Renault, and Alain Prost, Ferrari 641.
Andrea de Cesaris, Dallara BMS-190 Ford, leads Nelson Piquet, Benetton B189B Ford, Gerhard Berger, McLaren MP4-5B Honda, Thierry Boutsen, Williams FW13B Renault, and Alain Prost, Ferrari 641.