The Tyrrell 001, which bore much resemblance to the MS80, emerged at the end of . It earned Stewart a pole position in the Canadian GP but suffered mechanical failures in all of its three race starts. The nearly identical Tyrrell 003 won both Drivers' and Constructors' Championships in , with strong driving from Jackie Stewart and François Cevert. Stewart's 1972 challenge was ruined by a stomach ulcer, but he returned to full fitness in 1973. He and Cevert finished first and fourth in the Championship, but Cevert was killed in practice for the final race of the season, the US Grand Prix at Watkins Glen. Stewart, who was to retire at the end of the season, and Tyrrell immediately stood down, effectively handing the Constructors' title to Lotus. At the end of the season Stewart made public his decision to retire, a decision that was already made before the US Grand Prix. Without their star driver or his skilled French protégé aboard, Tyrrell were never serious World Championship contenders again.