"It's working alright, and now it's showing. I feel like I'm driving pretty good, and the team's doing a good job. We just need to keep doing what we're doing, and results like this will keep coming."
Jack Daniels Racing's Rick Kelly fought back for a strong fourth.
"We had a tough start to the weekend and I'm really stoked that we managed to fight back to get a fourth," said Rick Kelly.
"We were still a little bit behind others as far as track time because of practice. We fixed a couple of little things on the car to get more pace and we will definitely be in line to get a podium at this event.
"We just need to keep trying to finish in the top five and top three to get points and momentum for the Championship."
Whincup's back-to-back gives him 300 championship points into next weekend's second round of the Series at the Gulf Air Desert 400 in Bahrain, while Winterbottom (267 points) is second.
Whincup's teammate Craig Lowndes, who was fifth in Saturday's race, is third in the Championship with 249 points.
To see the race result in full, click here