Nicki Pedersen became the first double grand prix winner in 2012 and closed to within six points of Greg Hancok in the standings with victory in Croatia.
The Danish rider made a fantastic start in the final from the unfancied second gate to take the lead and that is where he stayed right to the flag.
He did have a brief moment in the final, though, when second placed man Andreas Jonsson hit his back wheel, but, somehow both riders managed to stay on their bikes to finish first and second.
Wildcard entry Jurica Pavlic impressed at his home race as he picked up two wins on his way to the final, but, in the end his inexperience told as he came in last. However, the 23-year-old showed enough pace to be considered one to watch for the future.
Australian Chris Holder, who was already suffering with an injury, fell in heat 14 when his chain broke and he was fired into his handle bars as he rounded turn 1, before sliding into the barriers.
He required medical attention and despite wanting to take part in heat 20, took the decision to sit the race out. "I could go out there and race," Holder said. "But, if I fell off again that could be the end of year for me."
British rider Chris Harris had a good night, reaching the semi-finals and finishing fifth in the standings.
The 'Bomber' recovered from finishing fourth in his first heat, to take two race wins and a second, finishing with 10 points, which moves him to 12th in the standings, 24 points behind the top 8 riders.