The 23-year-old travelled to Norway in a fine run of form that has seen him top the podium three times in his last six outings – and he ensured that continued.
Watabe set himself up for gold with an impressive ski jump – his leap of 107m giving him an overall total of 135.3 and a cushion of 20 seconds going into the cross-country ski.
Tino Edelmann jumped 104.5m for 130.3 overall and second while Bernhard Gruber, despite recording a distance of 105.5m, only scored 130.1 and was a further second behind in third.
But neither were able to topple Watabe as he stormed around the cross-country course and crossed the finishing line in first in a winning time of 26:21.4minutes.
Mikko Kokslien made up a 58-second cushion after scoring just 120.9 after the ski jump to take silver almost eight seconds behind the runaway Japanese winner.
That pushed Edelmann out of second with the German seventh but Gruber did hold on for third, 1.7seconds behind Kokslien, with fourth-placed Norwegian Joergen Graabak 32.7 shy of Watabe.
And, with World Cup leader Jason Lamy Chappuis’ inconsistent form continuing, Watabe closed the gap on the Frenchman to 72 points with his total now 1202.
Lamy Chappuis was always going to be out of contention after ranking just 31st following the ski jump but did improve to 23rd with his leading total 1274.