America's greatest skier of all time had previously announced this season would be her last.
In the final 20-kilometer mass start, Diggins looked to be heading for a dream finish on home soil and was in the fight for the podium, but with barely two kilometers left, the American fell and the chance disappeared.
"It was amazing, so many people in the audience. I felt like I was racing for the whole world," she told Norwegian Viaplay, according to NTB.
Instead, it was a blue-and-yellow dominance when the competition was decided. Jonna Sundling was the strongest and won, almost four seconds ahead of Linn Svahn. Norway's Heidi Weng finished third.
"It was tough out there. I might have had a bit of luck getting on the podium," said Linn Svahn, who finished the World Cup season with two wins and a second place, to Viaplay.
In the overall World Cup, Diggins' fall did not play a role. She had already secured the victory. Second came Moa Ilar and third Maja Dahlqvist.
Final top five in the overall Women's Cross-Country Skiing World Cup.
1. Jessie Diggins, USA, 2,227 points
2. Moa Ilar, Sweden, 1,854 points
3. Maja Dahlqvist, Sweden, 1,587 points
4. Jonna Sundling, Sweden, 1,308 points
5. Heidi Weng, Norway, 1,207 points
