PORT Adelaide tagger Kane Cornes could shape the result of Saturday's preliminary final through his match-up with one of Hawthorn's stars, according to brother Chad.

There are two leading candidates to earn the Cornes tag at the MCG, with in-form midfielder Sam Mitchell and damaging runner Brad Hill both familiar with the run-with specialist.  

After averaging 25.5 disposals in the first 16 rounds this season, Cornes has returned to permanent lockdown duties the past two months with his own output dropping by five touches a game.

His success at the MCG on Saturday evening, however, will be measured by Mitchell or Hill's impact on the game.  

"He's not getting the possessions he once was, but he's playing a really vital team role," Chad, a former teammate of Kane's at Port Adelaide, but now an assistant coach at GWS, told AFL.com.au.

"If you've got Kane coming to you before the bounce you know you're going to be in for a really tough day.

"As we know, Hawthorn have got so many great players and his match-up could go a fair way to deciding the result."

When Port Adelaide beat Hawthorn in round 10, Mitchell was missing and Cornes split his time between Hill and All Australian Jordan Lewis.

Hill had five possessions in 29 minutes opposed to Cornes, while a rampant Lewis was shut down and restricted to three possessions in 23 minutes under the Power tagger's watch.

In his most recent match-up on Mitchell, in round 16 last season, Cornes kept the former Hawks skipper to 14 possessions in 75 minutes.

Mitchell's brilliant form in Hawthorn's qualifying final win over Geelong could convince Power coach Ken Hinkley to send Cornes to the 31-year-old.  

"I know he's done some great jobs on Mitchell before," Chad said.

"When he told me he was tagging Hill that first time I was a little bit unsure, and it’s not the match-up I would have picked, just because of the difference in leg speed.

"But the thing about Kane is he always finds a way – he's one of the most mentally tough players I ever played with.

"Whoever he gets he'll study them through the week and find the best way to beat them."

Cornes has run with contrasting opponents in the Power's two finals this year, with differing results that could dictate his target this week.

According to Champion Data statistics, he spent 22 minutes on Richmond captain Trent Cotchin in the elimination final at Adelaide Oval, holding him to one possession in that time.  

Against Fremantle at Patersons Stadium last Saturday, he spent 54 minutes on Stephen Hill, who had 15 possessions against him.  

"I don't think it was his best game on the weekend against Fremantle," Chad said.  

"He really got Hill the two previous times, but by Kane's own admission it wasn't his best game on the weekend.

"The week previous to that, I think his job on Cotchin was really good against Richmond, and his games leading into the finals were really good as well."

Cornes admitted to some bias but he believed his brother was tagging as well as anyone in the competition this season.

Indeed, the Power veteran's career revival has been superb since the end of 2011 when he was told by then coach Matthew Primus that he wasn't part of the club's future plans.

He earned a reprieve and has since played 69 of a possible 70 games, equalled Warren Tredrea's club record of four best and fairest awards, and overtaken him as the Port Adelaide games record holder.  

"When I was coming up to GWS in 2011, he was really close to leaving," Chad said.

"I remember having a chat to him and him saying, 'That's probably it, I'm ready to retire'.

"The club was ready to pay him out, but thankfully CEO Keith Thomas came in and said, 'We're not treating a club champion like that'.

"I'd say when he looks back on his career when it's finished, these past two years will be right up there as his most enjoyable."