Justyna Kowalczyk (POL) destroyed the women’s field over the second 5k of the 10km classic in front of frenetic home crowd in Szklarska Poreba, Poland.
Five seconds up on rival Marit Bjørgen halfway through, Kowalczyk opened up a 27 seconds gap over the next two kilometers.
The victory, with Bjørgen just holding onto second ahead of teammate Therese Johaug, gave Kowalczyk back the overall World Cup lead.
Norway took places 2-5 in the race, but no one was able to challenge Kowalczyk at the front.
Kikkan Randall skied a strong race on a day where waxing was a nightmare.
The American placed 8th, just seven seconds out of 5th.
Her teammate Ida Sargent had a career day in World Cup distance racing, finishing 26th.
Sargent was one place behind the top Canadian, Dasha Gaiazova.
Liz Stephen faded after a good start placing 38th on the day.
Alysson Marshall was 55th for Canada while Perianne Jones did not start.