The 32-year-old produced jumps of 130.5 and 132.5 metres and beat Norway’s Halvor Egner Granerud and Austrian Stefan Kraft to snatch his sixth career win.
The second-highest placed Pole, Piotr Żyła, was 5th, while Poland's three-time Olympic champion, Kamil Stoch, finished tenth.
Kubacki, who last year snatched the bronze at the 2022 Winter Olympics, had a remarkable run during the Summer Grand Prix, becoming the record-holder in the number of summer event victories and winning the whole competition.
Sunday will see another World Cup individual competition at Wisła’s Adam Małysz Ski Jumping Hill, named after one of the most successful athletes in the history of ski jumping, who currently serves as president of the Polish Ski Federation.
The 2022-23 season will feature 32 events and will draw to an end on 2 April.
(pjm)
Source: PAP