The Wanganui racer dominated the weekend topping the timesheets in free practice and qualifying, before taking the chequered flag for the second time this season.
Bamber was made to work hard in the early stages after losing the lead to Nicki Thiim on the opening lap. The Kiwi reclaimed the position on lap six and once in front he cruised to the chequered flag.
“Fastest in free practice, pole position, victory and now the points' leader – what a perfect weekend. I'm over the moon,” said Bamber.
Bamber's victory has opened up a three point lead over Kuba Giermaziak in the championship.
Ferrari junior driver Rafaele Marciello recorded a maiden GP2 Series race victory after coming through a titanic scrap with Stoffel Vandoorne at Spa.
The feature race was interrupted by a heavy rain shower which halted proceedings before being restarted under the Safety Car.
Marciello ran third in the early stages before passing Johnny Cecotto jr in pursuit of leader Vandoorne.
After emerging behind the McLaren junior after the mandatory pit stop, the Italian eventually caught and passed Vandoorne with just two laps remaining.
Cecotto Jr was third ahead of title contender Felipe Nasr and New Zealand's Mitch Evans, who was lucky to finish after a mechanical problem forced him into a spin.
Nasr reduced championship leader Jolyon Palmer's advantage to 32 points with his fourth win of the series in the sprint race. Cecotto Jr was second ahead of Palmer and Evans.
Auckland ace Evans is fifth in the championship standings after two strong points finishes.
Tauranga's Richie Stanaway remains in the hunt for a maiden GP3 title despite being denied a third win of the year by Alex Lynn.
The Kiwi briefly took the lead on the opening lap after Lynn made a mistake, but he was unable to keep the Brit behind him.
Just two seconds separated the pair at the flag while Alex Fontana finished a distant third.
Dean Stoneman made the most of a decision to run slick tyres on a damp but drying track as he went on to take his second win of the year in the opening race.
After inheriting the lead early on, the Brit finished ahead of fellow countrymen Dino Zamparelli and Nick Yelloly. Stanaway came home in seventh ahead of Lynn in eighth.
Lynn leads Stanaway by 32 points ahead of the next round at Monza in two weeks' time.
Honda's Matt Neal, Airwaves Racing's Mat Jackson and West Surrey Racing's Rob Collard picked up their first victories of the season as the British Touring Car Championship ventured to Scotland's Knockhill circuit.
The triple BTCC champion spent the early stages of race one in fifth before surging up through the field by passing polesitter Sam Tordorf, Rob Austin, team-mate Gordon Shedden and reigning champion Andrew Jordan.
Neal went on to take his first win behind the wheel of the Civic Tourer from Austin and Shedden, while championship leader Colin Turkington retired.
Jackson ended a win drought of almost two years for Motorbase Performance in race two after he inherited the lead from Neal, who was given a penalty for a jump start.
Plato finished second for MG with Austin on the podium again in third.
Collard won the reverse grid race having battled from sixth on the grid to take the chequered flag in the WSR BMW from Dave Newsham and Turkington.
Turkington holds a 23 point lead over Shedden in the standings.
Blancpain Sprint Series
Team Schubert's Dominik Baumann and Thomas Jager produced an impressive come from behind win in the Blancpain Sprint Series main race at the Slovakia Ring.
Having retired from the opening race, the BMW pair scythed their way through the field from the back of the grid.
The pair moved into fifth spot after a stunning opening lap before a slick pit stop strategy helped them to victory, taking the lead with just two laps remaining.
Caca Bueno and Sergio Jimenez finished second just 1.5 seconds behind the winners, while WRT Audi's Rene Rast and Enzo Ide came home in third.
New Zealand's Chris van der Drift finished fifth.
WRT Audi pair of Laurens Vanthoor and Cesar Ramos came through to win a twice red flagged qualifying race on Saturday.
The first stoppage was caused by a huge crash for Reiter Lamborghini's Tomas Enge, who escaped a frightening series of end over end rolls. Heavy rain later on saw the race come to a halt once again.
In the end, Ramos held his nerve to take the chequered flag from the Grasser Lamborghini of Hari Proczyk and Jeroen Bleekemolen. The HTP Mercedes of Maximilian Gotz and Nico Verdonck was third.
United Sportscar Championship
Risi Competizione won an all GT United Sportscar race at Virginia Raceway after Giancarlo Fisichella put a move on leader Wolf Henzler on the final lap.
The Rahal Letterman BMW of John Edwards and Dirk Muller claimed the final spot on the podium
Turner Motorsport's Markus Palttala and Dane Cameron took the honours in the GTD class.
VIDEO Blanpain Sprint Series – Tomas Enge escapes huge shunt
VIDEO Blancpain Sprint Series Main Race