South African Robbie Hunter and Laszlo Bodrogi of Hungary were among the big names to abandon the men’s cycling road race here Saturday, the Olympics’ first major endurance event held in sweltering conditions.

Both riders pulled out prior to the halfway stage of the 245km race, being held in hot and humid conditions with a persistent haze shrouding the concluding 23.8km hilly loop, which is raced seven times. “It was very hard, the humidity was very high,” said Bodrogi, who as a time trial specialist is not best suited to the hilly Olympic course. “I had difficulty on the climb. It was better for me just to do one lap so I am fresher for Wednesday’s time trial.”

Organisers announced the temperature at 26 degrees celsius but with humiditiy at 90 percent the peloton were promised a tough day in the saddle.

Dutchman Niki Terpstra was an early victim, while Bolivia’s Horacio Gallardo – an early race leader along with Patricio Almonacid of Chile – pulled out not long after the first of the seven climbing loops began.

Terpstra, who took part in his first Tour de France in July, said he pulled out after doing his job. “It was my job to be in the first attacking group. Then I fell back and I tried to get back in the first group but just couldn’t,” he said. “It’s just so difficult. It’s like a sauna.”

Raivis Belohvosciks of Latvia, who was one of the riders in a 27-man escape group that held a five-minute lead on all the big favourites with just over 100km to race, also pulled out.

In the heat of Athens in 2004, only 75 of 144 riders finished the men’s Olympic road race that was won by Italian Paolo Bettini.

As Saturday’s race headed towards an exciting finale with a 24-man chase group being pursued by a peloton with all the pre-race gold medal favourites, American David Zabriskie was among several other riders to pull out.

Like Bodrogi, he is hoping to keep some energy for the mid-week time trial but admitted the course was a tough nut to crack. “There’s not one easy part on this course. Even the downhill is difficult,” said the American.

Argentina’s Alejandro Borrajo and Matias Medici also abandoned, leaving their last teammate Juan Jose Haedo – a sprinter – on his own. Further abandons were Bulgarian Daniel Petrov, Great Britain’s Jonathan Bellis and former German champion Gerald Ciolek.