 The 312PB dominated the World Sportscar Championship in 1972 against a rival Alfa Romeo, as the Porsche factory did not compete after the rule changes, and Matra focused on Le Mans only.In their home race, the French won, as Ferrari did not enter in 1972 due insufficient reliability over 24 hours, in order not to blemish their otherwise perfect record in that season.In 1973, though, the Matra team also challenged for the championship which Ferrari eventually lost with two wins, compared to Matra's five, while Alfa Romeo had not entered that year.