Clark win in a Lotus; the next three races were won by fellow-Briton Graham Hill, each time in a BRM. Hill's 1964 win enabled him to carry a points advantage into the next and final race in Mexico. 1966 and 1967 saw Clark win; the '66 win was the only Formula One race he won that year, driving a Lotus with an overweight BRM H16 engine. Both the Drivers' and Constructors' championships were clinched at the event by Australian Jack Brabham and his Brabham team. In 1967, Clark dominated, leading comfortably from his teammate Hill and Denny Hulme in a Brabham. In 1968, Mario Andretti put his Lotus 49 on pole position in his first Formula One race. But Andretti retired, and Briton Jackie Stewart won the race in a Ford/Cosworth-powered Matra. Austrian Jochen Rindt won in 1969 – his first Formula One race win. He took advantage of Stewart's mechanical problems to pull a huge gap out on the rest of the field. Graham Hill had a much worse day. He punctured his car's rear right tire and the rubber came off the rim. The rubber exploded, sending the Lotus cartwheeling off the course, and Hill was thrown out of the car, breaking both legs. Due to USGP's position on the calendar near the end of the season, often either the final or penultimate round, championships were often decided before the event. In part to offset this, race organizers offered large sums of prize money; in 1969 the purse totaled $200,000 (with $50,000 for the winner), and when in 1972 it was raised to $275,000, the Tyrrell team earned a record $100,000. 1970s 1970 saw Brazilian newcomer Emerson Fittipaldi win the race in just his fourth Formula One start. Stewart retired his new Tyrrell and Fittipaldi, driving a Lotus, held off a charge from Mexican Pedro Rodriguez in a BRM. It was an emotional win for Colin Chapman's Lotus team, as team leader Rindt had been killed while practicing for the Italian Grand Prix at Monza. Lotus had not run the Canadian Grand Prix, but because the next closest championship contender Jacky Ickx did not score enough points to keep him in contention, the Drivers' Championship was won by Rindt posthumously at this race. Team Lotus also won the Constructors' Championship at the 1970 event. In 1971, the course was changed considerably. The entire lower section of the track