Home favourite Hellner won the first event of the 2010-11 men's Nordic skiing World Cup on Saturday when he took the honours in the 15km at Gällivare in Sweden.
Hellner, a double Olympic champion this year, completed the course in 33min 36sec, 11.4sec ahead of Switzerland's Dario Cologna and 20.1sec faster than third-placed Swede Daniel Rickardsson.
The 25-year-old Swede also won over the same distance in Gällivare in 2008, in what was his only prior success on the World Cup circuit.
Norwegian world number one Petter Northug is skipping the early part of the season due to injury, while Norwegian biathlon king Ole Einar Bjørndalen finished 25th on one of his rare forays into Nordic skiing.
Earlier in the day, triple Olympic champion Marit Bjørgen of Norway won the first event of the 2010-11 women's Nordic skiing World Cup on Saturday when she claimed victory in the 10km freestyle.
The 30-year-old romped home in 23min 48.4sec to record her 38th World Cup victory.
Sweden's Charlotte Kalla, the Olympic champion in the category, finished 41.1sec back in second place, with Italy's Arianna Follis third at 51.4sec.
Poland's Justyna Kowalczyk, the reigning world number one, finished in a modest seventh place, 1min 15sec off the pace.
Bjørgen, who won five medals at the 2010 Winter Olympics in Vancouver, is the big favourite ahead of a season that will feature the 2011 World Championships in front of her home fans in Oslo.
The Gällivare event concludes on Sunday with the relays.