Yulia Stupak and runaway leader Alexander Bolshunov helped Russia secure a cross-country skiing World Cup double with victories at Engadin.
Bolshunov has worn the yellow bib since December and has long since wrapped up the overall title, adding yet another win to his collection in the 15km classic mass start.
The 24-year-old was 16th at the first checkpoint but cruised from thereon to stop the clock in 34:07.1, 18 seconds clear of the rest of the field.
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Johannes Hoesflot Klaebo took silver for Norway while bronze went to his compatriot Paal Golberg after the two sprinted for the line in Switzerland.
Just the 50km freestyle pursuit remains in the World Cup calendar with Bolshunov free and clear in both the overall and distance standings.
Ivan Yakimushkin is second in both with Russian athletes taking the top six spots in the distance standings in the battle for the red bib.
Stupak, meanwhile, won a World Cup race for the second time this season to add to the plethora of podiums secured across the campaign.
A time of 25:13.3 was enough for victory in the 10km classic mass start, with Heidi Weng of Norway and Sweden's Ebba Andersson taking silver and bronze respectively.
Jessie Diggins, who has already secured the yellow bib, came home fifth.
Stupak's gold takes her within one point of second-placed Andersson in the red bib standings with Sunday's 30km freestyle pursuit remaining on the agenda.
Yuliya Stupak doubles for Russia with 10km Mass Start victory
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