IN-FORM Port Adelaide full-back Alipate Carlile says the Power can't expect to keep winning while they're defending 70 inside 50s a game.

The Power had the answers at the right times against Adelaide on Sunday night, kicking away late to win by 24 points.

But they conceded 71 inside 50s in Showdown XXXVIII, after withstanding a ferocious second-half blitz against Hawthorn in round five.

As important as the victories have been, they've come while giving up a combined 150 inside 50s across the two games. The Power are playing unsustainable football, according to coach Ken Hinkley.

Carlile has been superb over the past fortnight, keeping Hawks spearhead Jarryd Roughead goalless and then Crows skipper Taylor Walker to just two goals on Sunday.

He credited Port's midfield for helping to limit the impact of the opposition's attacking drives.

But he agreed with his coach that failure was inevitable if the inside 50 trend continued.

"It's something that we're going to have to work on because obviously Kenny said that we can't keep defending like this," Carlile said.

"But to the backs' credit, we've been holding up pretty strong.

"We're getting a fair bit of support from the mids with the pressure that's coming inside, which is obviously making it a bit easier to defend, but just weight of numbers, we won't be able to keep this up much longer."

Carlile was full of praise for the five other members of Port's back six.

The 28-year-old is one of the form defenders of the competition after his stunning fortnight, but pointed out that Jasper Pittard, Matthew Broadbent and Jack Hombsch were also flying.

Pittard in particular has begun season 2015 in tremendous fashion and averages 24 disposals a game, up from 16 a game last year.

"It's probably been the best as a back six we've started," Carlile said.

"Jasper's going brilliantly; having Nathan Krakouer down there gives us another option coming out of defence, Broady's (Broadbent) been unreal and Jack Hombsch is doing his job."