Peterson made his Grand Prix debut in a March 701 for Colin Crabbe's works-supported Antique Automobiles Racing Team at the 1970 Monaco Grand Prix. The limited budget of Crabbe's privateer team allowed only minimal testing, and Peterson qualified 12th out of 16 cars in the race. He was 10 places behind Jackie Stewart and Chris Amon, both on the front row of the grid in their newer specification 701s, but only just behind the more experienced Jo Siffert in the second works March. Peterson was the only March driver to finish the race, in seventh place. In 1971 Peterson moved up to the full March works team, and made an instant impression. Five Formula One Grand Prix second places earned him the position of runner-up to Jackie Stewart in that year's World Championship. Within that year, Peterson drove in the World Sports Car Championship driving an Autodelta Alfa Romeo to win the Watkins Glen 6 hours. Peterson stayed at March until 1973, when he signed for John Player Team Lotus to partner Emerson Fittipaldi.