The Holden Racing Team gun backed up his win on the streets of Adelaide this time last year in a fight to the flag ahead of Shane Van Gisbergen and HRT team-mate Garth Tander.
Courtney was intent on letting six-time Champion Jamie Whincup know that he was in his sights and he delivered. Whincup was there and thereabouts all day but didn't have the final push to challenge his rival Holdens in the late stages.
Despite that, Courtney stopped just short of claiming HRT was now the benchmark team, notwithstanding his victory today and second in yesterday's final race.
"I think still we have some areas to clean up. Today they (Red Bull Racing Australia) probably dropped the ball and we were running with our ‘A' game," Courtney said.
"Last year, towards the end of the year, we had really strong speed, just the reliability wasn't there. A lot has been put in place since but we have a way to go.
"It was good to drive away from them. It was a good feeling to see that car going backwards in the mirror. We are working hard to be that team but Triple Eight are still the benchmark team we are all chasing.
"Garth and I are here to win the Championship. We don't care who is in front of us. We are massively hungry. The speed of the car is great so it is up to us to work together and park the egos within the team."
Courtney and Van Gisbergen have had some cracking battles over the years and this was amongst the best. Courtney had to use all his guile to fend off the flying Kiwi as Tander ranged menacingly behind, waiting for one or both to make an error.
"I was just sitting back enjoying the show hoping the fireworks would start. I was an insurance policy back there just making sure one of the HRT cars was on the top step," Tander said.
Van Gisbergen passed Courtney with five laps to go after a nudge, but the Kiwi redressed and let his opponent back into the lead. He also nudged his rival on the final corner but Courtney deemed it a clean fight.
"There was a bit of pressure. He was really quick, had a really good go. It was great sportsmanship when we came together. It was great to race so hard but to do in that manner," said Courtney.
"It was about five to go I hit the wall and broke the mirror off so I couldn't see. I trusted that he was going to do the right thing. I always knew there was going to be a lunge when we were coming out of eight. We had the right car speed at the right places to keep him out."
Van Gisbergen said he had matured from the raw racer that had no fear a few years back, hence his show of sportsmanship and level head in the final laps.
"A younger Shane would have and probably hit something. It's just years. I've learnt. I have broken a few front bumpers off in my time," Van Gisbergen said.
"It was an awesome race. Through the middle I didn't really know what was happening with strategy. I just enjoyed that last stint so much. I had one good go at him. Epic race. It was really cool. The last lap through turn eight was awesome. Really enjoyed it."
While all eyes were on the front of the field in the closing lap, Jamie Whincup tapped Chaz Mostert pushing for fourth. The Pepsi Max driver had James Moffat plough into his Falcon, with big damage on both the Falcon FG X and Nissan Altima. Officials were looking into the incident.
"I am gutted," Mostert said. "To be on the last lap of the Clipsal 500 with a good bag of points in line and to get nothing is tough. I am not quite sure what happened to be honest. He had a 10 car-length gap on me and as I came out of turn eight that was gone."
His teammate Mark Winterbottom managed fifth, with yesterday's race two winner Fabian Coulthard sixth on the road.
Whincup and Red Bull teammate Craig Lowndes were uncharacteristically fighting back in the pack, with Whincup finishing fourth and Lowndes ninth, declaring a lack of pace.
Scott McLaughlin had more alternator dramas with his Volvo S60, with both Erebus cars also in and out of the garage throughout the 78 lap mini-marathon.
Returning star Marcos Ambrose finished 12th after his top 10 qualifying effort as DJR Team Penske continue to make their way up the grid. Ambrose' next Championship event is in his hometown Launceston, following the Australian Grand Prix in Melbourne.
His new boss Roger Penske was on hand all weekend to watch his debut and declared he was happy with the progress of his team and the former back-to-back Clipsal 500 winner.
The Nissan Altimas of Moffat and Rick Kelly were racy. Moffat was an early challenger before the Whincup/Mostert clash killed his hopes of a top ten finish. Kelly finished seventh and his older brother Todd in tenth.