Flintoff admitted nerves had played a part as England ended day two of the most-hyped series in cricket history at 53 for three in reply to Australia's mammoth first innings total of 602 for nine declared.
But the champion all-rounder insisted his team's character meant they were fired up despite their first Test mauling at Brisbane's Gabba.
"We're not deflated," he told reporters Friday. "It's the first two days of the Ashes series.
"Tomorrow we're going to have to come out and bat well, we need some partnerships and some runs on the board.
"There's lot of character in this side and we're up for the challenge of the series so after two days we're not going to be deflated, we've just got to get better."
Flintoff, who has been England's singular outstanding performer over the two days, said his team had now experienced the big-match atmosphere of an Ashes Test in Australia and had to put any nerves aside.
"Going into a series like this you expect a few nerves knocking around," he said.
"It's a young side and turning up to play in a game of this magnitude (means) there will be nerves.
"But the lads have experienced it now and they know what to expect for the rest of the games."
He praised England's players for giving their all, saying they now "just have to get on with it" against their old foes Australia.
"It's been two hard days, Australia played well and I thought we stuck at it, in patches we did alright," he said.
Flintoff also defended England's misfiring bowling spearhead Steve Harmison, who leaked 123 runs for just one wicket off 30 overs in Australia's first dig.
"He got better throughout the innings, when it's not going well it does knock your confidence a little bit and Harmy's just striving to get back to his best," he said.