Canadian cross-country skier Alex Harvey's free fall in the Tour de Ski continued Friday with a 37th-place finish in the sixth stage in Dobbicao, Italy.

Harvey, who had climbed to eighth spot Tuesday, only to fall to 10th by the following day, is now 15th overall.

Finn Haagen Krogh of Norway won Friday's 10-kilometre freestyle pursuit in 22 minutes 7.8 seconds for his seventh career victory. Martin Johnsrud Sundby finished second, 3.6 seconds behind, and Maurice Manificat of France was third, 14.6 back.

"I have had some ups and downs in the Tour de Ski this year. I had to believe there is a good day ahead of me," Krogh told reporters. "It is great to win and to beat Martin. He has been very strong the whole year and it is a great victory for me.

"I maybe started little bit too hard and around the halfway of the race it was difficult for me. But in the end I knew I could win and I just gave everything I had."

The 27-year-old Harvey, who hails from St. Ferreol, Que., stopped the clock in 23:13.6.

Sundby re-established a comfortable lead over Norwegian teammate Petter Northug Jr. in the overall standings.

Healthy lead

Northug placed 15th in the stage, 34.5 seconds behind, and trails Sundby, the two-time defending champion, by 1:28.1 in the overall standings.

"I have again a good gap but I don't take anything for granted," Sundby said.

Sergey Ustiugov of Russia was third overall, 3.7 seconds behind Northug.

Krogh moved up from seventh to fourth overall.

In the women's 5km race, Jessica Diggins of the United States claimed her first career win in 13:15.5, finishing ahead of four Norwegians.

Heidi Weng was second, 0.9 behind, followed by Ingvild Flugstad Oestberg, 1.5 back.

Oestberg increased her overall lead ahead of Therese Johaug, who was fifth in the stage, to 25.3 seconds.

Diggins became the second American to win a stage this season after Sophie Caldwell took the fourth leg.

"It's really fun that we have such a strong team," said Diggins, who has won two medals at the world championships. "This was a big surprise for everyone, most especially me."

The eight-stage race concludes on Sunday with the traditional climb up Mount Cermis in Val di Fiemme. 

With files from The Associated Press