 Complete the following phrase:  The Williams FW15C was an extremely domit car, with active suspension and traction control systems beyond anything available to the other teams. Prost won on his debut for the team in South Africa and, like Mansell, dominated the weekend, taking pole position and finishing a minute ahead of Senna, who was second. The next Grand Prix in Brazil saw Prost collide with Christian Fittipaldis Minardi in the rain on lap 29, while Hill went on to his first podium finish: second, 16 seconds behind Senna. Prost won three of the next four Grands Prix for Williams, Senna winning the other race. Prost and Hill later scored a 12 in France: the only 12 of the season for Williams. Prost won the next two Grands Prix at Silverstone and Hockenheim. Hill proved competitive especially in the second half of the season. Mechanical problems cost Hill leads in Britain and Germany, but he went on to win the next three Grands Prix at 