Tour De Ski winner Jessie Diggins outgunned Therese Johaug and strengthened her grip on the yellow jersey with 10km freestyle victory in Falun.
The American took the Tour De Ski crown in defending champion Johaug's absence last month and again stamped her authority on the field in the free technique with a knife-edge win in Sweden.
Norway have missed most of the season due to COVID-19 concerns and Diggins's victory laid down a marker for February's World Championships, opening on 23 February.
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Diggins was out-split by the world No.1 at the first and final checkpoints but ploughed time into Johaug in the middle section to prevail by just 2.1 seconds.
Sweden's Ebba Andersson was the only racer to keep in touch with the top two, cutting the tape 14.1s back, with the next four finishers Norwegians.
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