The Norwegian topped the pile in the sprint event, the third of this year's Tour, to leapfrog compatriot Marit Bjoergen, who ended up 13th on the day, opening up a two-second lead.
Fellow Norwegian Astrid Jacobsen finished second in the sprint event in Switzerland meaning she climbs to fourth in the overall standings.
Denise Hermann of Germany prevents a Norwegian 1-2-3 on the podium as she currently sits third, 2.3seconds back from Oestberg.
In the men's sprint Simeon Hamilton of the USA claimed his maiden World Cup win while compatriot Alex Harvey strengthened his lead in the overall standings.
Hamilton stormed down the final straight to cross the line first with Harvey having to settle for second on the day.
Norway’s Martin Sundby was third while Brits Andrew Musgrave and Andrew Young both qualified through to the last 30 but could not advance to the latter stages. © Sportsbeat 2013