The New Zealand cricket captain says the inability to cope against the second new ball decided their fate in the first test against South Africa in Cape Town.
Brendon McCullum's Black Caps have lost by an innings and 27 runs at Newlands
With Dean Brownlie scoring 109, his maiden test century, New Zealand defied South Africa's bowling attack for most of the third morning before succumbing to the second new ball.
232 for five at lunch became 275 all out in their second innings shortly before tea.
McCullum watched his side lose their last six wickets for 46 runs.
The second and final test will start next Friday in Port Elizabeth.