information:classification
1971: A third consecutive Tour and second world championship

Faema folded at the end of the 1970 season causing Merckx and several of his teammates to move to another Italian team, Molteni. The first major victory for Merckx came in the Giro di Sardegna, which he secured after attacking on his own and riding solo through the rain to win the race's final stage. He followed that with his third consecutive Paris–Nice victory, a race he led from start to finish. In the Milan–San Remo, Merckx worked with his teammates in a seven-man breakaway to set up a final attack on the Poggio. Merckx's attack succeeded and he won his fourth edition of the race. Six days later, he won the Omloop Het Volk.

After winning the Tour of Belgium again, Merckx headed into the major spring classics. During the Tour of Flanders, Merckx's rivals worked against him to prevent him from winning. A week later, he suffered five flat tires during the Paris–Roubaix. The Liège–Bastogne–Liège was held in cold and rain conditions. After attacking ninety kilometers from the finish, Merckx caught the leaders on the road and passed them. He rode solo until around three kilometers to go when Georges Pintens caught him. Merckx and Pintens rode to the finish together, where Merckx won the two-man sprint. Instead of racing the Giro d'Italia, Merckx elected to enter two shorter stages races in France, the Grand Prix du Midi Libre and the Critérium du Dauphiné, both of which he won.

The Tour de France began with a team time trial that Merckx's team won, giving him the lead. The next day's racing was split into three parts. Merckx lost the lead after stage 1b, but regained it after stage 1c due to a time bonus that he earned from winning an intermediate sprint. During the second stage, a major break with the major race contenders, including Merckx, formed with over a hundred kilometers to go. The group finished nine minutes ahead of the peloton as Merckx came around Roger De Vlaeminck during the sprint to win the day. After a week of racing, Merckx held a lead of around a minute over the main contenders. The eighth stage saw a mountain top finish to Puy-de-Dôme. Bernard Thévenet attacked on the lower slopes and Merckx was unable to counter. Joop Zoetemelk and Luis Ocaña went with Thévenet and wound up gaining fifteen seconds on Merckx.

On the descent of the Col du Cucheron during the race's ninth leg, Merckx's tire punctured, prompting Ocaña to attack with Zoetemelk, Thévenet, and Gösta Pettersson. The group of four finished a minute and a half ahead of Merckx, giving Zoetemelk the lead. The following day Merckx lost eight minutes to Ocaña after a poor showing due to stomach pains and indigestion. At the start of the eleventh stage, Merckx, three teammates, and a couple of others formed a breakaway. Merckx's group finished two minutes in front of the peloton that was led by Ocaña's Bic team. After winning the ensuing time trial, Merckx took back eleven more seconds on Ocaña. The race entered the Pyrenees with the first stage, into Luchon, being plagued by heavy thunderstorms that severely handicapped vision. On the descent of the Col de Menté, Merckx crashed on a left bend. Ocaña, who was trailing, crashed into the same bend and Zoetemelk collided with him. Merckx fell again on the descent and took the race lead as Ocaña was forced to retire from the race due to injuries from the crash. Merckx declined to wear the yellow jersey the following day out of respect for Ocaña. He won two more stages and the general, points, and combination classifications when the race finished in Paris.

Seven weeks following the Tour, Merckx entered the men's road race at the UCI Road World Championships that were held in Mendrisio, Switzerland. The route for the day was rather hilly and consisted of several circuits. Merckx was a part of a five-man breakaway as the race reached five laps to go. After attacking on the second to last stage, Merckx and Gimondi reached the finish, where Merckx won the race by four bike lengths. This earned him his second rainbow jersey. He closed out the 1971 calendar with his first victory in the Giro di Lombardia. This victory meant that Merckx had won all of cycling's Monuments. Merckx made the winning move when he attacked on the descent of the Intelvi Pass. During the off-season, Merckx had his displaced pelvis tended to by a doctor.