As an amateur in January Krekels was very successful at the Olympic Games in Mexico in 1968, he won the gold medal in the team time trial, together with Joop Zoetemelk, René Pijnen and Fedor den Hertog; in the individual road race he finished eleventh. Previously, he had been recommended by his victories in the Tour of Austria and other races like the Ronde van Overijssel and the Omloop the Kempen.
1969 Krekels was professional. He won the 1970 Eight van Chaam and 1972, the Ruta del Sol. In 1977 he became Dutch vice-champion in the road race. Three times he competed in the Tour de France, in 1971, he won the 19th stage.