The Olympic champion added the missing final prize to his trophy cabinet at the joint World Cup and European Championships for bobsleigh and skeleton in Winterberg.
With a pushing crew of Thorsten Margis, Candy Bauer, and Alexander Schueller behind him, Olympic and world champion Friedrich also set a new start record of 4.96 seconds in the first four-man competition of the season.
The World Cup event also doubled up as the 2021 European Championships for athletes from countries in Europe, meaning that Friedrich has now won all four major four-man bobsleigh titles.
Silver went to Canada, piloted by two-man Olympic champion Justin Kripps and his team of Ryan Sommer, Cam Stones, and Benjamin Coakwell.
It was a successful return to action for Kripps, who was competing for the first time in more than a year after sitting last season out to rest his body.
Finishing with World Cup bronze and European Champs silver was the Austrian team of Benjamin Maier, Sascha Stepan, Markus Sammer, and Kristian Huber.
European bronze went to junior world champion Rostislav Gaitiukevich, alongside Mikhail Mordasov, Ilya Malykh, and Ruslan Samitov from Russia.
It has been a stellar weekend for 30-year-old Friedrich, who also sealed his fifth European Champs two-man title on Saturday alongside Margis.
That victory drew him level with compatriot Andre Lange for the most World Cup pilot victories with 45.
His Sunday win moves Friedrich clear as the most successful male pilot, and level with fellow German Sandra Kiriasis, who retired with 46 women's event wins.
There was more success for Germany, with World Cup and European Championship silver going to 2019 mixed team world champion Johannes Lochner and Eric Franke.
Bronze went to Benjamin Maier and Markus Sammer - Austria’s first two-man bobsleigh European Championship medal since Walter Delle Karth in 1973.
Friedrich’s victory means he pulls further ahead In the IBSF World Cup overall two-man rankings with 2,010 points, ahead of Lochner on 1,849.
It was another German team in Laura Nolte and Deborah Levi who were victorious in the two-woman bobsleigh competition.
The duo posted the fastest times in both runs of the competition on home ice to take home the World Cup and European Champs gold medal.
Their compatriots Kim Kalicki and Ann-Christin Strack finished in second, while third was shared between Austria’s Katrin Beierl and Jennifer Onasanya and German pair Mariama Jamanka and Leonie Fiebig.
Junior world champion Kalicki's team remains top of the World Cup standings on 1,030 points, ahead of Beierl (978) and Nolte (885) respectively.
If Germany were the stand-out team in bobsleigh, the top marks in the skeleton go to the Russians.
Third went to Alexander Gassner from Germany.
Dukurs remains top of the overall World Cup standings on 1,110 points, with Gassner his nearest challenger on 946.
Tretyakov’s compatriot Elena Nikitina defended her European title in the women’s race with a dominant run.
Germany's Tina Hermann was edged into silver by 0.06 seconds, with Austria's Janine Flock completing the podium with bronze.
Flock remains her overall World Cup lead with 1,075 points, ahead of Dutch slider Kimberley Bos with 998.