think it's easier to contol the run rate batting second. how would you go about aggressively trying to limit a team to 150 on a pitch where 250 is doable? at least batting you can hit out from the start.
And when they chase the bowling from the off it could be catastrophic.
To win batting first you build a strong platform and try to bat the Sri Lankans into a position where they are chasing 350 and they have to chase from the off.
There is no control trying to score 250 off 29 overs, their only hope either way was for Sri Lanka to be bowled out cheaply and with no pressure on the Sri Lankans batting first that 'plan' fell away fairly quickly.
Bottom line is they faced an almost impossible ask, batting first they might have got into a strong enough position to apply pressure but short of knocking 4-5 early Sri Lankan wickets down, bowling first they couldn't control it bowling first any more than they could bowl Sri Lanka out for 150 bowling second.
Or put another way, to chase down 250 they'll probably need to be about 100/1 or 100/2 after about 15 overs, if they could get anywhere near 250 off 29 overs then imagine how relatively easy it would be to score 350+ , a mere 7 an over compared to the 8.62 required to chase 250 down in 29.
The Sri Lankans may well profit from a foolhardy mission, and the aussies suffer because some idiot let them bat 50 overs and that meant the kiwis got to only bat 15 thus producing no result which may well cost the aussies dear.
It's ironic the kiwis haven't been great, just crawling past West Indies in a low scorer, 51/2 off 15 overs against the aussies when rain ended the match, and beaten by England when the total was well and truly gettable. Yet they may well reach the semis because of NRR and the weather
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This will be good, if they can chase it down. Sri Lanka are probably going to use Malinga a lot early on
Sri Lanka only need to keep their heads and let the aussies lose their's. Plenty of slower balls, Yorkers, and a few short balls and the aussies should serve up a fair few catching chances and exposed stumps.
The aussies have to make all the running, that said Sri Lanka must not just sit back. They need to bowl normally, if they try only to contain like England probably would then they may well lose. They have to remember they need to win the game, not just stop the aussies scoring the runs in 29 (or whatever) overs.