Since being stripped of the inaugural World Cup title she won last year after a fourth successive victory for Takanashi in Ljubno on February 17, Hendrickson hasn't given her rival a sniff.
The 18-year-old American first won the world title in Val di Fiemme last month and then the first World Cup event since in Trondheim on Friday before repeating the trick in Oslo.
World Cup champion Takanashi was second at the World Championships and second in Trondheim and had to make do with the same finish at the last round of the season in Norway.
Hendrickson achieved more style points than Takanashi to lead after the first round, her jump of 133.5m giving her a total of 132.3 with her rival leaping 134m but scoring just 130.4.
Takanashi again produced a far bigger jump during round two, 133.5m compared to 129m from Hendrickson, but she wasn't awarded the style points as she had to settle for second.
Hendrickson won with a total of 262.8 with Takanashi just two points behind in second while Jacqueline Seifriedsberger jumped from sixth after round one to finish third.
The Austrian ended with 233.9 points with Coline Mattel of France fourth with 221.5, Elena Runggaldier of Italy fifth with 217.4 and Carina Vogt of Germany sixth with 216.1.