Didier Pironi of France led from the third lap on yesterday to win the Dutch Grand Prix by 21 seconds over Brazil's defending world champion, Nelson Piquet.

In cool, overcast weather, Pironi drove a faultless race in his Ferrari V6 and had a 44-second lead over Piquet's Brabham at one stage. Finland's Keke Rosberg placed third in a Williams, followed by Austrian Niki Lauda (McLaren), Ireland's Derek Daly (Williams) and Italy's Mauro Baldi (Arrows).

Pironi's major challengers, compatriots Rene Arnoux and Alain Prost, both driving turbocharged Renault Turbos, dropped out during the first half of the 72-lap race totaling 190.23 miles. Arnoux crashed into a barrier of tires after losing his left front wheel at the end of a straightaway in the 21st lap, but was unhurt, and Prost returned to the pits in the 32nd lap with a blown engine . . .

At Daytona Beach, Fla., Joe Ruttman had the fastest lap in the final qualifying session for the Firecracker 400 Grand National stock car race. Ruttman toured the 2.5-mile, high-banked Daytona International Speedway oval at 190.367 mph to take the 21st position in Sunday's 40-car field.

Geoff Bodine, a Grand National rookie, won the pole position at 194.721 mph, breaking Cale Yarborough's Firecracker qualifying record of 194.670, set in 1980.

Others qualifying yesterday included 18-year-old Bobby Hillin Jr., a Texas high school senior, and 56-year-old country-western singer Marty Robbins.