The rauf hat trick changed the game.
You gotta give credit to good bowling. Pitch wasn't difficult beyond uneven bounce
Target was 200 - Aussies knew they can coverup mini collapse. Chasing a target like 200, you can adopt both options - blast away and bring the target so close that asking rate is out of question and even the tail can score few runs that left. Or, you can make sure that you don't loose early wicket and near the target methodically for one last final push. Aussies tried first one and today almost lost the game. Had the target been 250, it would have been all together a different ball game - Aussies would have known that they won't get away with against a penetrative attack without one big or couple of significant partnerships. You probably have noticed, for DWL target setting, every team will take 200 in 20 overs than 300 in 50.
And, this is not a new tactics - that Kanpur ODI where Afridi scored 100 of 44, PAK was chasing 240ish total and ball was supposed to take turn later - so, plan was to go after early and bring the target to a level from where middle order can push around for singles and chase the rest - it over-clicked that day hence PAK won inside like 35 overs, 4 or 5 down, had it been 128-4 after 15, still would have won because target was 240, may be for 8/9 down and inside 48 overs. But, it didn't work at Bangalore 1996 - PAK was 85/0 after 10, 115/2 after 15 and 134/4 after 20 ..... because, target was 289 - India had the space to make a come back through wickets. That would have been the difference of a target between 203 and 245 on that MCG track last night.
Even then, had PAK fielded well, taken their catches, a bit more disciplined about extras, .... Aussies would have lost this game!!!!
No, the wicket wasn't that easy - of all the demons on wicket, ask any batsman, he'll say that the most disturbing element is uneven bounce - it doesn't allow batsmen to be assured of going to front foot or back foot - you can leave moving or turning balls on length or line if it's consistent on bounce, but not so easy if it's uneven. On a more even & easy paced track, I am 100% sure Babar would have been full stressed forward and would have survived that flipper from Zampa which kept a shed low from length, while Rizwan won't have ever miscued a sweep, that bounced more than he expected - he is a master of that shot at least. And, Abdullah got one that jumped a foot higher than his expectation to kiss the edge....
Besides, never underestimate the size of the boundary - 10 metres hardly matter against modern compressed bats, most of the sixes these days easily clear 70+ metres... BUT, but you need lot, lot more guts to loft knowing that the rope is 10 metres behind. And, that out field cost both teams at least 10-12% runs. Slow outfield on a smaller ground hardly matters because the scoring shots are mostly one or boundary; but it matters massively on larger grounds - a boundary can end up just for a couple or even single.
Anyway, Aussies got their lesson that PAK attack will hurt them if they are not careful - it's not the cannon fodder Pom attack; I am sure they'll be more methodical in next two games.