The Pole followed up his victory in the opening event of the season in Auckland with a triumph on home shale at the Edward Jancarz Stadium.
Hampel stormed past world champion Chris Holder on the first lap with the Australian taking second ahead of Brit Tai Woffinden and Greg Hancock.
Emil Sayfutdinov maintained his position at the top of the overall standings with 84 points ahead of Woffinden (73), Holder (68) and Hampel (66).
The 31-year-old Hampel, who started the night with just a point from his opening two rides and only edged into the semis on countback, said: “It was my first Grand Prix win in Poland and what can I say? It was an amazing feeling. We had thousands of people in the stadium and the crowd was really wild when I started in the final.
“When I got in front, I felt all the people stand up around me and that was really cool.
“I had a pretty quick bike before the final and it’s really important to take your chance if it comes. I did that when I raced behind Chris very closely. When he made that mistake, I tried to take my chance and go for it.
“Early in the meeting, it was very tough and it was a shame I couldn’t race better from the beginning. I made the wrong choice between the lines, even when I won the start, and everybody passed me very easily. It was very important to think about the races every single time and in the end, I knew what the best line was and I took it.”
World Championship leader Sayfutdinov exited the event at the semi-final stages with 15 points to extend his lead over second-placed Woffinden from eight points to 11 at the summit.
But it was a remarkable performance from the 22-year-old from Scunthorpe who was racing just 12 days after undergoing surgery to plate and screw the collarbone he shattered at the British GP in Cardiff.
WORLD CHAMPIONSHIP STANDINGS: 1 Emil Sayfutdinov 84, 2 Tai Woffinden 73, 3 Chris Holder 68, 4 Jaroslaw Hampel 66, 5 Nicki Pedersen 64, 6 Niels-Kristian Iversen 60, 7 Greg Hancock 57, 8 Tomasz Gollob 52, 9 Krzysztof Kasprzak 48, 10 Matej Zagar 48, 11 Fredrik Lindgren 47, 12 Andreas Jonsson 39, 13 Martin Vaculik 33, 14 Antonio Lindback 26, 15 Darcy Ward 25, 16 Ales Dryml 7, 17 Chris Harris 7, 18 Krzysztof Buczkowski 6, 19 Linus Sundstrom 6, 20 Bartosz Zmarzlik 6, 21 Josef Franc 2, 22 Jason Bunyan 1, 23 Craig Cook 1, 24 Josh Auty 1.
GORZOW SGP POINTS: 1 Jaroslaw Hampel 14, 2 Chris Holder 14, 3 Tai Woffinden 12, 4 Greg Hancock 12, 5 Emil Sayfutdinov 15, 6 Niels-Kristian Iversen 11, 7 Krzysztof Kasprzak 10, 8 Andreas Jonsson 9, 9 Nicki Pedersen 8, 10 Fredrik Lindgren 7, 11 Matej Zagar 7, 12 Bartosz Zmarzlik 6, 13 Martin Vaculik 4, 14 Tomasz Gollob 4, 15 Antonio Lindback 3, 16 Ales Dryml 2, 17 Adrian Cyfer DNR, 18 Lukasz Cyran DNR.
- Sports & Recreation
- Chris Holder
- Emil Sayfutdinov
- Greg Hancock