It doesn't help when you play 3 specialist bowlers.
Against the Proteas we defended 185.
Against Australia, we prevented them from going 200+. The score they put up was definitely chaseable given how small the boundaries were--Rohit Sharma was smashing mistimed shots for six at the end of it. So although our bowlers leaked runs there, I think it was a good enough track that if we had one guy who could stick there at the top, we would have made a game of it.
Against West Indies, we restricted them to 169, which was about par (Sri Lanka restricted Australia to 168 in the following match). Again, our batsmen could only put up 155.
Against Sri Lanka, our batsmen failed to capitalize on a good start on a dead pitch to put up only 163. Sri Lanka could have coasted to a victory there but they were playing it safe to make sure they got to the 143 magic marker first.
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In short, if we'd actually played a balanced side with 7 batsmen and 4 bowlers, our part-timers would have been useful since they wouldn't have been bowling the bulk of our overs. The part-timers definitely stung since they bowled overs and overs of long hops which were easy pickings for international batsmen.