The victories made it four wins in a row for Rea, and eight out of 10 races so far this season.
In the first race, championship leader Rea and Kawasaki team-mate Tom Sykes quickly pulled clear and fought for the lead right to the end, with Rea winning by just half a second.
The race had been shortened following a fall by David Slalom after 11 laps, effectively turning it into a six-lap shootout – and Rea took advantage of a missed gear change by Sykes to claim the lead and then hold on for his seventh victory in nine races so far this season.
“I thought the six-lap race might favour my rivals but I pushed to the maximum and Tom made a mistake which allowed me to take my chance and pull away,” said Rea after race one.
Giugliano was third, with Nicky Haslam fourth and Sylvain Guintoli fifth.
In the second race, Rea pulled well clear of the field with quite outstanding pace, Rea finishing well clear of Sykes with Jordi Torres coming third and Giugliano fourth.
Sykes had challenged early on, but Rea kept him at bay and eventually finished over four seconds clear to extend his championship lead to a staggering 83 points.
The measure of the Kawasaki dominance enjoyed by Rea and Sykes was further underlined by the margin to third place: Torres was 26 seconds off Rea’s pace.