Clark made his
Formula One (F1) Grand Prix debut, part-way through the season, during the
1960 Dutch Grand Prix at Zandvoort on 6 June. Lotus had lost Surtees, who took part to the
Isle of Man TT series; alongside
Innes Ireland and
Alan Stacey, Clark was one of the substitutes deemed acceptable. He retired on lap 49 with final drive failure. His second Formula One race was the
1960 Belgian Grand Prix, held at the
Spa-Francorchamps circuit, where he finished fifth and scored his first
points finish. In the
1961 Italian Grand Prix on 10 September at
Monza,
Wolfgang von Trips in his
Ferrari collided with Clark's Lotus. Von Trips's car became airborne and crashed into a side barrier, fatally throwing von Trips out of the car and killing fifteen spectators. Clark and his car were subjected to an investigation; he was initially accused of manslaughter, before the charges were dropped. At the time, Clark described the accident by saying: "Von Trips and I were racing along the straightaway and were nearing one of the banked curves, the one on the southern end. We were about 100 metres from the beginning of the curve. Von Trips was running close to the inside of the track. I was closely following him, keeping near the outside. At one point von Trips shifted sideways so that my front wheels collided with his back wheels. It was the fatal moment. Von Trips's car spun twice and went into the guardrail along the inside of the track. Then it bounced back, struck my own car and bounced down into the crowd." In his later testimony, he recalled the collision had become unavoidable, saying: "Trips was head of me, driving on the center of the track. Suddenly he slowed down. Since my Lotus was faster than the Ferrari, I tried to overtake him. In the same instant the Ferrari surprisingly pulled to the left, and a collision became unavoidable..." Clark's first Drivers' World Championship came driving the
Lotus 25 in , winning seven out of the ten races and Lotus its first Constructors' World Championship. The
1963 Indianapolis 500 saw Clark's debut in the series; he finished in second position behind Parnelli Jones and won
Indianapolis 500 Rookie of the Year honours. The 1963 Indy 500 result remains controversial. Before the race,
United States Auto Club (USAC) officials had told the drivers that they would
black flag any car that was seen to be leaking oil onto the track. Late in the race, Jones' front-engined roadster developed a crack in the oil tank and began to leak oil. With the track surface already being slippery this resulted in a number of cars spinning and led to popular driver
Eddie Sachs crashing into the outside wall. USAC officials were set to black flag Jones after the Sachs crash until his car owner
J. C. Agajanian ran down pit lane and somehow convinced them that the oil leak was below the level of a known crack and would not leak any further. Colin Chapman later accused USAC officials of being biased because Clark and Lotus were a British team with a rear-engine car. Many, including journalist and author
Brock Yates, believed that had it been an American driver and car in second place instead of Clark in the British built Lotus, officials would have black flagged Jones. Despite this, neither Lotus nor their engine supplier
Ford protested the result, reasoning that winning as a result of a disqualification when Jones had led for 167 of the races 200 laps (Clark led for 28 laps) and had set the lap record speed of on lap 114, would not be well received by the public. In , Clark came within just a few laps of retaining his World Championship crown. As in 1962, an oil leak from the engine cost him the title, conceding to John Surtees. Tyre failure damaging the Lotus's suspension put paid to that year's attempt at the
1964 Indianapolis 500. He made amends and won the Championship again in , and also won the
1965 Indianapolis 500 in the
Lotus 38. He had to miss the prestigious
1965 Monaco Grand Prix to compete at Indianapolis but made history by driving the first
mid-engined car to win at the fabled Brickyard, as well as becoming the only driver to date to win both the Indy 500 and the F1 title in the same year. Other drivers, including Graham Hill,
Mario Andretti,
Emerson Fittipaldi, and
Jacques Villeneuve, also won both crowns but not in the same year. in 1966 The FIA decreed that from new 3-litre engine regulations would come into force, and Lotus were less competitive. Starting with a 2-litre
Coventry-Climax engine in the
Lotus 33, Clark did not score points until the
1966 British Grand Prix and a third place at the
1966 Dutch Grand Prix. From the
1966 Italian Grand Prix onwards, Lotus used the highly complex
BRM H16 engine in the
Lotus 43 car, with which Clark won the
1966 United States Grand Prix. He also picked up another second place at the
1966 Indianapolis 500, this time behind Hill. During , Lotus and Clark used three completely different cars and engines. The Lotus 43 performed poorly at the opening
1967 South African Grand Prix, so Clark used an old Lotus 33 at the
1967 Monaco Grand Prix, retiring with
suspension failure. Lotus then began its fruitful association with
Ford-Cosworth. Their first car, the
Lotus 49 featuring the most successful
F1 engine in history, the
Ford-Cosworth DFV, won its first race at the
1967 Dutch Grand Prix, driven by Clark. He won with it again at the 1967
British,
United States, and
Mexican Grands Prix, and at the
1968 South African Grand Prix. Concurrent with competing in the F1 World Drivers' Championship, Clark competed with Lotus in the
Australasia-based
Tasman Series, run for older F1 cars. He was series champion in
1965,
1967, and
1968. He won fourteen races in all, a record for the series. This included winning the
1968 Australian Grand Prix at the
Sandown International Raceway in
Melbourne, where he defeated the
Ferrari 246T of
Chris Amon by just 0.1 seconds after 55 laps of the 3.1 km (1.92 mi) circuit, the closest finish in the history of the
Australian Grand Prix. The 1968 Tasman Series and Australian Grand Prix would prove to be his last major wins before his death. ==Performances==