Frenzel became the individual World Cup champion elect with victory on Friday and he followed that up with another win in the team sprint with fellow German Johannes Rydzek.
The 24-year-old and Rydzek led from start to finish in Finland with their 18-second lead after the ski jumping becoming a winning margin of 21.8 after the cross country.
They were awarded 250.4 points for their efforts during the jump with the win Frenzel and Germany's third straight in the team events after successes in Chaux-Neuve and Sochi previously.
Frenzel will now turn his attentions to officially securing his first individual World Cup title with two events scheduled at the last round in Oslo and his lead currently 186 points.
Meanwhile the French team of Jason Lamy-Chappuis, who is about to relinquish his World Cup title won for three seasons running to Frenzel, and Francois Braud finished second.
They placed fifth after the ski jumping with 230.6 points but moved up the field to finish 21.8seconds behind Frenzel and Rydzek while a second German pair were third in Lahti.
Fabian Riessle and Tino Edelmann made their way up from seventh to third less than a second behind Lamy-Chappuis and Braud and 22.7 behind their victorious compatriots.