Complacent, on his second outing after almost two years off the course, returned to form by making all in the Group Two Tattersalls Club Chelmsford Stakes over a mile at Royal Randwick on Saturday, September 5.
The five-year-old Authorized horse was nearly carried out on his August 22 comeback but this time was sent to the front by Sam Clipperton and remained there.
Trainer John O'Shea had Hartnell, with James McDonald in the saddle, as well as Complacent in the contest.
Hartnell, having his first start of the season, raced in fourth of the 16 runners and then second but he could not find more when Complacent kicked for home a furlong and a half out.
Complacent came home unchallenged, winning by a length and a quarter from the late finishing Kermadec, with four-year-old Hartnell, also by Authorized, a further length and three quarters in arrears.
The winning time was 1m 37.68s on soft ground.
John O'Shea commented: "It is not anything I have done with Complacent, it is more about the team at Osborne - our vets Trevor Robson and Graham Adams plus Paul Reid and all the team at Osborne have been working on this horse for two years.
"He is a great horse and presented beautifully. His work on Wednesday was first class and he has raced up to his work - it is very rewarding for everyone.
"Complacent flew the barriers, controlled the race from the front; it was an advantage being on-speed today. He handled the soft ground, having had the run two weeks ago, and it was a great return to racing.
"Hopefully, we can keep him sound and I am sure that is not the last win he will have this season.
"He needs to stay in Sydney because we only have one Osborne Park. The facility, with the great tracks we have there, helps keep him sound and the team have plenty of time to work on him which helps us train him. We will have a chat about where to go next.
"When Hartnell doesn't get cover, he travels a bit keenly, and he did that today. This was his first run back after a spell which was a disadvantage as he didn't have the benefit of an earlier run as Complacent did.
"I thought the effort was there, we just need to concentrate on getting Hartnell some cover in his next races."
Sam Clipperton added: "That was all right. Complacent just did that on his ear - he got into a lovely rhythm and was happy. From the 550 (metres out), he just got quicker and quicker and built. At the furlong, I could sense there could be a challenge and he found more - it was a very impressive win.
"It was my plan to be closer in the run, though not necessarily in the lead. We drew well and there was not much speed inside us. He landed in front with a lot of ease and once I was there I wasn't worried.
"He was enjoying himself - his ears were pricked - and he went up through his gears really well. We are going to take a lot of confidence out of that win and he can go on to bigger and better things.
"He is already a good horse - he won a Group One doing something similar - but has been off the scene for a long time."