Brad Haddin remains hopeful of Australia launching a second-Test fightback after England took control on day two in Adelaide.
Alastair Cook's second successive century helped England close on 317-2 in their first innings, already a lead of 72.
The opening batsman finished unbeaten on 136 and, following on from his 235 not out in the series opener, has not been dismissed for nearly 17 hours.
Wicketkeeper Haddin conceded a long day chasing leather in sweltering conditions had left Australia not at their "perky best".
But he insists the tourists have not given up on the match and will return on day three with renewed optimism.
"Obviously it's been a tough day, but we've got to make sure we fight," he said. "Test cricket's not meant to be easy.
"But if we keep presenting ourselves, and show we're hungry and really want to be in this contest, this game can turn."