The 34-year-old produced jumps of 105 and 102.5 metres to finish ahead of Germany's second-placed Karl Geiger and Slovenia's third-placed Anze Lanisek.
Norway's Halvor Egner Granerud, who leads this season’s World Cup standings, missed the podium, coming in fourth.
Poland's defending normal-hill world champion Dawid Kubacki finished fifth.
Countryman Kamil Stoch, a three-time Olympic champion, was 22nd.
Twenty-three Polish athletes are competing in the 2021 Nordic World Ski Championships, which run until March 7 in Oberstdorf.
Team Poland includes 11 ski jumpers, both men and women, 10 cross-country skiers, and two Nordic combined competitors.
Poland won two medals, gold and silver, when the championships were held in Seefeld, Austria, two years ago.
Source: PAP, TVP