- Marit Bjoergen wins her third medal of PyeongChang 2018
- Bjoergen ties Ole Einar Bjoerndalen as the most-decorated Winter Olympian
- The "Iron lady" has chance to break the record later in the Games
The 37-year-old Bjoergen, nicknamed the "Iron Lady", pulled away from Sweden's Stina Nilsson in the last 500 meters of the race to take gold, with the Norway team clocking a time of 51 minutes, 24.3 seconds at the Alpensia Cross-Country Center.
Bjoergen is now level with legendary compatriot and fellow cross-country skier Ole Einar Bjoerndalen, with the chase to break the record outright still to come later in the Games.
Sweden finished just two seconds behind its neighbor while the Olympic Athletes from Russia took bronze, 43.3 seconds back.
Bjoergen collapsed onto the snow after crossing the finish line before celebrating with her teammates Ingvild Oestberg, Astrid Jacobsen and Ragnhild Haga.
Norway had been lying in third place when Bjoergen started the final leg of the relay. Although Nilsson pushed Bjoergen hard, she was never able to overtake her, and with the finish line in sight, the Norwegian found an extra gear to ski into the history books.
Bjoergen has now won seven gold medals from five Olympics, trailing only Bjoerndalen and Norwegian cross-country skier Bjoern Daehlie, who each have eight.
She could overtake biathlete Bjoerndalen as the world's most decorated winter Olympian later in the week, either in the 30 kilometer race on the final day of the Games, or in the team sprint if she is selected.
Bjoergen, who gave birth to a baby boy at the end of 2015, had already become the most successful female winter Olympian on the first day of competition in Pyeongchang when she won silver in the 15-kilometer skiathlon.
Five days later, she claimed bronze in the 10-kilometer free before finally winning gold in the relay.