During a long and exhausting day in which the six finalists in each of the men's and women's races skied four races, Norway won both events at the Olympics for the first time.
The men's final was highlighted by a collision that wiped out half of the six competitors. Minutes before that, Sophie Caldwell delivered the best showing ever for an American woman in an Olympic cross-country event.
In order to reach the finals of the Olympic sprint, a contestant must survive a qualifying round, then must finish high in both a quarterfinal and semifinal heat.
By the time the finals roll around, there is not much left in the tank for those still competing for the medals.
That was made clear in the men's final, when Emil Joensson of Sweden slowed dramatically in the opening moments of the race and let the other skiers go on without him.
As the race played out, however, a Russian, a Norwegian and a Swede became involved in a chain reaction crash and all three went down.
That left Hattestad and Teodor Petterson to fight it out for the gold medal and Hattestad prevailed in a time of 3:38.39. Petterson finished 1.22 seconds behind.
Back on the course, meanwhile, Joensson reached the site of the collision and he passed all three of the fallen skiers as they tried to get back on their feet. Now realizing he had a chance to win a medal, Joensson summoned his last bit of energy and held off Anders Gloeersen to claim the bronze.
Joensson collapsed at the finish line and remained sprawled on the snow for several minutes before members of the medical staff arrived to help him to his feet.
Falla won the women's race by 0.38 of a second over another Norwegian -- Ingvild Flugstad Oestberg. The bronze medal went to Vesna Fabjan of Slovenia.
Caldwell narrowly missed winning her semifinal heat, but she qualified for the finals and by doing so ensured she would finish no worse than sixth. No American woman had ever had so high of a placing in an Olympic cross-country race.
A medal actually seemed possible for Caldwell considering how well she had skied through the day, but after putting herself in good position early in the finals she tripped up on a ski pole being carried by Sweden's Ida Ingemarsdotter and that mishap caused the American to fall.
Caldwell finished 12 seconds behind the winner and six seconds behind the fifth-place Ingemarsdotter.