The former DTM competitor and his 2011 Bathurst 12 Hour winnning co-driver led from start-to-finish on Sunday to add the championship race victory to the qualifying race win achieved on Saturday.
The opening race was less straight forward for the pair, as they picked through the opening lap carnage from 10th on the grid.
Winkelhok described the championship race as ‘easy.'
“It was easy actually,” he said.
“First of all the pitstop was good, the car was just great and the balance was in the car after the first few laps.
“It couldn't have been much better than yesterday, but even at the end I was able to attack and get good lap times.
“I'm so happy, I think we definitely took the maximum out of the weekend. For sure it won't be easy next weekend with so much ballast, and I have never driven at Portimao, but hopefully we can be strong again.”
Christian Hohenadel and Andrea Piccini took second in the championship race after a lightning fast Hexis Racing pitstop propelled the Aston Martin up the order.
A day earlier Piccini had crashed out of the qualifying race as Basseng challenged for the lead.
Alex Muller and Tomas Enge made it two Astons in the top three in the championship race, finishing ahead of a tight battle between the Karl Wendlinger/Peter Kox Swiss Lamborghini and the Mike Hezemans/ Nicky Catsburg China Corvette.
Australian David Brabham and co-driver Jamie Campbell-Walter had a disastrous weekend, with Campbell Walter involved in an opening lap crash the sister Sumo Power Nissan on Sunday after also failing to finish on Saturday.
Basseng and Winkelhock now lead the Drivers' Standings on 49 points ahead of Stef Dusseldorp and Clivio Piccione on 36 points, while the Hexis Aston Martin squad lead All-Inkl in the Team's Standings by 66 points to 49.
The FIA GT1 World Championship now heads to Algarve, Portgual for Round 3 on May 7-8.
Here is the race start crash involving Jamie Campbell-Walter