But this time, the roles were reversed, as Sundling took gold, beating Svahn into silver to deny her teammate a clean sweep of golds in New York state, following her victories in the 10km classic and sprint freestyle.
Sundling completed the course in 48:17.1, 3.5 seconds clear of Svahn, going on one final attack in the closing stages to put daylight between herself and the chasing pack.
Heidi Weng of Norway finished third as the top seven all finished within 10 seconds of each other in a tight race. Weng took her second bronze medal of the week, making her the only non-Swedish woman to take a medal in the female events.
The Swedish dominance was by no means straightforward on the final day, as overall World Cup winner Jessie Diggins was determined to bow out in style on what is expected to be her final race at the top level.
The American was battling for a podium position on home snow, but disaster struck two kilometres from the finish, when the 34-year-old fell and her chance had gone.
Diggins eventually finished 12th, one place ahead of Moa Ilar of Sweden, who completed the World Cup in second overall. Frida Karlsson, who picked up a silver in the 10km classic, finished 15th, while sprint champion Maja Dahlqvist crossed the line in 23rd place.
Johannes Hoesflot Klaebo signed off another dominant season with victory in the men's race, beating Harald Oestberg Amundsen by less than a second, as Einar Hedegart completed the Norwegian clean sweep of the podium. Eric Rosjoe was the best-placed Swede, finishing 27th.