The two-time world champion was forced to settle for second in the sprint but blew that out of the water with 100 per cent accuracy at the shooting range to cross in 31:44 for the victory.
Home favourite Emil Hegle Svendsen was 31.2 seconds behind in silver, thanks to two penalties, while Russian Evgeniy Garanichev completed the podium in third.
Despite finishing second Svendsen retook the overall World Cup lead as he now leads France’s Martin Fourcade by a single point after the Frenchman could only finish fourth in Oslo.
Meanwhile, Germany’s Magdalena Neuner took her second victory in a row as she stormed to women’s 10km pursuit victory in Oslo.
The 24-year-old double Olympic champion crossed the finish line in 30:31.1 minutes with two penalties for victory, with Russia’s Olga Zaitseva and Darya Domracheva taking silver and bronze respectively.
In claiming her second victory in the space of three days Neuner stretched her overall World Cup lead to 75 points from Belarus’ Domracheva, much to her surprise as she admits she is still feeling the effects of illness.
“It is amazing for me to win,” she said. “It is nice to know I am in this shape.
“It has not been an easy week as you can see from my voice that I am a bit sick.
“I was focused at the shooting range. If I was completely healthy, then maybe I would win.”