In March 1966, Merckx entered his first major stage race as a professional rider, the Paris–Nice. He took the race lead for a single stage before losing it to Jacques Anquetil and eventually coming in fourth overall. Milan–San Remo, his first participation in one of cycling's Monuments, was the next event on the calendar for Merckx. There, he succeeded in staying with the main field as the race entered the final climb of the Poggio. He attacked on the climb and reduced the field to a group of eleven, himself included. Merckx was advised by his manager to hold off on sprinting full-out to the finish line until as late as possible. Three other riders reached the line with him; Merckx, however, beat them in the sprint. In the following weeks, he raced the Tour of Flanders and Paris–Roubaix, the most important cobbled classics; in the former he crashed and in the latter he had a punctured tire. At the 1966 UCI Road World Championships he finished twelfth in the road race after suffering a cramp in the closing kilometers. He finished 1966 season with a total of 20 wins, including his first stage race win at the Tour of Morbihan.