Hinkley has helped transform a Power outfit that won just five matches last season.
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Comfortable wins over Melbourne and GWS, followed by a stunning comeback victory in Sunday's Showdown against Adelaide, has Port Adelaide sitting behind Essendon on percentage only at the top of the ladder.
Hinkley returns to Metricon Stadium for the first time since leaving at the end of last season, with his undefeated Power sporting a 3-0 record.
Harbrow said he had been impressed by the Power, and was not surprised by Hinkley's impact.
"They've jumped out of the blocks firing, they're in good form, the players are happy and they look like they understand what Kenny wants and expects of them," he said.
"He's definitely brought an element to the club that's working.
"They look strong and are super competitive and we have to be on our best to match it with them. We can't give a side like them in the form they're in a head start in the first quarter."
Harbrow said he had also noticed an attitude shift around the Suns, now in their third season.
They were noticeably distraught after losing to the Brisbane Lions last week.
"I think every match we play and every loss we have is going to sting," he said.
"It's our third year now and the days of saying we're inexperience and are the new guys have gone out the window.
"We see ourselves as a competitive AFL team. We want to attack each game like it's our last."
After two years as an assistant to Guy McKenna, Hinkley built a strong bond with a number of the Suns' younger players, but Harbrow said sentiment would play no part on Saturday.
"When Kenny was here he gave his all to the club and certainly helped the younger players, particularly the forwards and midfield group," Harbrow said.
"He's another enemy now, another coach coming on our turf to coach against us and get his team the win.
"We won't take it likely, we won't show any remorse that's for sure. We're going out there to try and beat Port Adelaide footy team."
Michael Whiting covers Gold Coast news for AFL.com.au. Follow him on Twitter: @AFL_mikewhiting
