Sandes, right, won the 125km Transgrancanaria in the Canary Islands, crossing the finish line in 14hr 27min 42sec.
Facing 8 500 metres of climbing in the Ultra-Trail World Tour race across the island of Gran Canaria, Sandes started slowly and was lying fifth at the 70km mark.
He took the lead with 17km remaining and drew nine minutes clear of Frenchman Julien Chorier, who was second in 14:36:28.
“That was my plan, to start off and take it easy,” Sandes said.
“I felt good in the second half, so I just kept on running.”
The South African, who won the shorter 83km race at Gran Canaria last year, said he would now return home as he aims for a record crossing of the Drakensberg mountain range with countryman Ryno Griesel, in an effort to add to his long list of achievements.
Sandes is the only athlete to have won every race in the Four Deserts Challenge, and last year became the first runner to win ultra-distance trail events on every continent.
The current record of two days, 12 hours, 29 minutes and 30 seconds for the Drakensberg Grand Traverse, a 220km hike from north to south, was set by Griesel and Cobus van Zyl in April 2010.
“In two weeks’ time we’ll make the Drakensberg record attempt,” Sandes said.
“This race was really good training for that, with all the climbing we’re going to have there.”