Niskanen completed the course in a time of 35min 17sec, 13 seconds quicker than his Norwegian rival.

Klæbo, who claimed victory in the sprint event yesterday, was forced to settle for second after crossing in 35:30.

Emil Iversen of Norway did enough for third, finishing in 35:31.9.

"It is for sure one of my fave places here in Ruka and I have to say that today there were more people on the track than ever, so it was an emotional feeling to cross the finish line," Niskanen said.

Ten-time world champion Therese Johaug, who missed last year's Winter Olympic Games in Pyeongchang because of a doping ban, triumphed in the women's 10km race.

The Norwegian crossed in 26:47.5, a full 30 seconds in front of nearest challenger Krista Pärmäkoski of Finland.

Natalia Nepryaeva of Russia came through to take third place in a time of 27:31.9.

"I am really happy to be back on the top of the podium again," said Johaug.

"Krista was starting 30 seconds in front of me, so I saw her and tried to push myself so in the second round we went together. 

"Of course I know that I have the preassure to go well tomorrow, but I know that I need good skis and a good shape. 

"But this day was really important for the mini tour and now I have a good chance to fight for the first place in the overall tomorrow."