Ireland boss Eddie O'Sullivan predicts the battle of wills fought on the sidelines will settle Sunday's collision with Australia at Lansdowne Road.
O'Sullivan promoted Isaac Boss, Bryan Young, Geordan Murphy and Denis Hickie to the starting line-up as Ireland target successive victories over major southern opposition for only the second time.
The Triple Crown winners dispatched South Africa 32-15 last Saturday but are braced for a more challenging test of their growing stock in Test rugby against the Wallabies.
With two dazzling backlines and similar sized packs, O'Sullivan claims the sides are so evenly matched the outcome will be decided by his coaching duel with opposite number John Connolly.
``We've lost our last four games on the bounce against Australia so the omens aren't good for beating them.
``Against Australia you don't know what is going to happen. It's a very tactical game and I enjoy that in the sense that there's a lot of coaching to be done on the day.
``You have to adjust the game-plan around what's happening in front of you. You have to have an open mind over where to attack.
``If you get it right you'll win, if you don't you won't - it's as simple as that.
``We're pretty evenly matched in all departments. Australia aren't much bigger than us and they don't have an advantage in speed.
``They're a very skilful team which is tactically well aware and the game will be won on tactics.''
O'Sullivan insisted the selection of Ulster scrum-half Boss, who will make his full Test debut with Peter Stringer dropping to the bench, would enhance his side's attacking options.
``Isaac is a more robust player than Stringer in some ways. He's more aggressive around the fringes. He likes to run and take on the back row in scrums and is a threat,'' he said.
Boss' Ulster team-mate Young will also make his full debut following three substitute appearances, with Marcus Horan dropping down to the bench.
Girvan Dempsey has been replaced by Murphy at full-back while Hickie comes in for Andrew Trimble who is still troubled by a recurring hamstring problem.