Aki isolates himself for that try, the outside defenders are all numbered up, meaning there's no real need for him to completely offload the ball carrier. There's a looping Australia attacker which Aki could number up against, but he's so far behind that by the point he would come into play, Australia would already be well beyond the gainline so that defensive alignment would be obsolete. His inside defenders are also equally at fault, but at the point screenshotted, Aki should be in a position to react and make the tackle, but he's so, so slow that Sua'ali'i just breezes past him with ease.
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This screen shot is too late though, famage has already been done by Curry shooting alone, and ball watching instead of scanning.
Infact if I remember correctly Sheehan pushes up, Curry goes with and marks a crash ball candidate, at that point Sheehan is basically touching Curry. Curry then sees the ball go behind the Aus play and decides to push on him instead of folding and cover Akis inside shoulder.
The line break is created through Curry's channel, whether Aki can turn in quick enough is pretty irrelevant, you have to trust your inside man in high level defences, a defender is never criticised for not turning in, because turning in as the outside defender is exactly what attacks try to acheive.
Curry gave away a number of line breaks because of this tendency,l to push and chase ball. Its not necessarily bad if its planned with those inside and out, but when its not its disruptive.
But look, noone has a perfect game, Curry isnt playing badly in the tests, he's just playing like he has all tour, at about 80% of what he's capable of.
In fact, he made 2 big tackles in the 1st test, doing this exact same thing, except on both occasions the pass had been made, and his contribution became neutral because he didnt stop anything or anyone