After a transitional year in which it had to make do with naturally aspirated Judd engines, starting in 1989 the Williams team signed a three-year agreement with Renault for the exclusive supply of the engine. The RS1, a 67-degree V10, had already run on the dyno in January 1988, before carrying out its first tests in the autumn, mounted on a Williams FW12 chassis. For the early part of 1989, the FW12 was modified to accommodate the Renault V10: the wheelbase was lengthened by approximately 15 centimeters. The car, called FW12C, proved to be quite competitive pending the FW13, expressly created for the Renault engine. Patrese finished second in three consecutive GPs, while Boutsen won his first career GP in Canada. Over the course of the season, however, the FW12C denounced all the limits of a non-definitive project, but due to the difficulties in setting up the new FW13 it was used up to the Spanish GP, where Patrese finished fifth.