The Norwegian star stopped the clock in a searing 27m29s on the Swedish slopes to win by a margin of 57.4s, holding off compatriots Heidi Weng and Ingvild Flugstad Oestberg to now sit 530 points clear at the summit of the table.
Oestberg - who is now sixth in the standings - trailed Weng by just 0.4s to clinch the final spot on the podium, with Weng now lying third in the overall table and 46 points adrift of Russia's Natalia Nepryaeva.
And Nepryaeva could only muster 12th in Ostersund as she languished with a time of 29m13.3s, finishing 1m44.3s behind Johaug who picked up her stunning 13th race victory of the season.
The 31-year-old also triumphed in Saturday's 10km F event in Sweden, where the podium looked identical to how it finished the following day.
And Paal Goldberg reigned supreme in the men's 15km C Pursuit, as he beat Alexander Bolshunov and Loewstroem Martin Nyenget to the line with a time of 34m50.8s.
Norwegian Goldberg - who is seventh in the overall table - toppled Russia's Bolshunov by just 0.3s, with Bolshunov nevertheless still sitting at the top of the table with a considerable 1,730 points.
And there was a surprise result in third as Goldberg's compatriot Nyenget beat Sjur Roethe by 0.4s to pick up the first individual podium of his World Cup career.
Bolshunov still possesses a significant 502-point lead over Hoesflot Johannes Klaebo - who only finished 25th in Ostersund - in the table, while Roethe lies third ahead of Sergey Ustiugov in fourth.
The cross-country World Cup season stays in Sweden and heads to Are next, where Bolshunov will be vying to get back to winning ways and Johaug seeking to maintain her dominance at the top of the standings.