 Complete the following phrase:  In the United States, the Castrol sponsored XJR-9s debuted at the 24 Hours of Daytona, with the car taking the overall win. However, throughout the rest of the IMSA Camel GTP season the XJR-9 was unable to gain another win until the final race of the season, meaning the team had to settle for third in the constructors championship. In the 1988 World Sports Prototype Championship, the XJR-9, running Silk Cut sponsorship, met with more success. The XJR-9 was able to take six victories, including the 