Jonathan Barragan took his second consecutive MX1 GP win after battling it out with fellow KTM rider Max Nagl, second overall, while defending champion Steve Ramon completed the podium in front of series leader David Philippaerts.
Ramon took his Teka Suzuki to victory in moto one, ahead of a battling Philippaerts and Barragan, with Nagl fourth after leading the opening laps.
The young German put up a stiffer resistance in race two, but was finally overtaken by Barragan with ten minutes of the moto remaining - allowing the Spaniard to secure his third victory of the season, while Nagl faced a determined attack from Sebastien Pourcel.
Josh Coppins - who collided with Pourcel early in race one, eventually finishing ninth - secured fourth in race two ahead of CAS Honda's Billy Mackenzie and his Monster Yamaha team-mate Philippaerts. de Dycker and Ramon completed the top eight.
In the world championship standings, Philippaerts is now eleven points clear of Ramon with Coppins a further twelve points back and badly in need of some good starts.
There was greater drama in the MX2 title fight when defending double world champion Antonio Cairoli injured his left knee in race one, leaving him pointless in both motos.
With arch-rival Tommy Searle taking a perfect double victory over team-mate, local star and world championship leader Tyla Rattray, the South African now holds a 21 point lead over the young Briton with Cairoli a worrying 59 points from the top.