After victory in Saturday's first event, the Norwegian ruled the roost once more to take top spot on the podium for the fifth time from five races this season.
As he did 24 hours previously, Riiber reigned supreme in the jump, scoring 152.8 points from his 139.5 metres though he had some work to do to avoid a crash in the finishing area.
Saturday had seen him enjoy a lead of more than 40 seconds heading into the cross country, though Sunday was a different affair with just four seconds his advantage prior to the second discipline.
It mattered little to the World Cup leader, however, victorious by 20.4 seconds ahead of teammate Jorgen Graabak who took home silver for the second time in two days.
Vinzenz Geiger and Fabian Reissle once again made up the top four though it was a role reversal this time around with Geiger taking bronze and his German teammate having to settle for fourth.
"I'm so happy to have five wins in a row, and having fun in competition," said Riiber. "I'm looking forward to a bit of rest before getting back to it over Christmas."
The 22-year-old's latest victory seems him atop the Nordic Combined World Cup standings with a perfect 500 points.
Graabak remains in second following his third successive silver-medal while Jens Luraas Oftebro completes an all Norwegian top-three, despite fifth and sixth-placed efforts over the weekend.
The World Cup calendar takes a short break before the first period concludes with a double-header in Ramsau am Dachstein from December 21-22.