The 29-year-old began his fine run of form with a third in Kazakhstan on February 12 and followed it up with another third as well as a second last weekend in Klingenthal.
And he ensured his upward trajectory continued in the Czech Republic as he ranked second after the ski jumping before powering around the cross-country course to take the win.
"The cross country track was very deep and very windy but I had to get on with my job and I did a great job and had a lot of power," said Gruber.
"I thought I started the first two laps of the cross country too fast but it was OK. I controlled the race from then onwards. The last round was really hard but I remained strong in the mind."
Gruber posted the second best score, 137.3, in the ski jumping and with teammate Wilhelm Denifl’s leading effort just 0.1 better there was no time difference to separate the two going in the cross country.
Denifl couldn’t match Gruber’s pace as he stormed to a winning cross country time of 27:29.6 minutes but he did hang on for his first-ever World Cup podium finish.
It has only taken Denifl 13 seasons and 172 starts to achieve the feat with the Austrian coming home third behind German Eric Frenzel who was 22 seconds shy of Gruber in second.
Mikko Kokslien was fourth after placing 17th in the ski jump, Akito Watabe ended fifth while World Cup leader Jason Lamy-Chappuis had a less than impressive day.
He was 41st after the ski jumping but did work his way to 21st in the end, despite a fall, and still heads up the overall World Cup rankings with 1173 points.