Home team retain squad, including tired bowlers, but focus is on paceman Steven Finn for the next challenge.
England players mentally resilient to stand Ashes grind, says Andy Flower
"We never for a moment thought that this match or the series would be a walkover," said Flower as he reflected on his side's 14-run win.
"I know we hear the odd thing in the media predicting some funny results, but we always knew this would be a tough battle. This is a really good example and I'm sure it will be a tough fight for the remainder of the series."
England named an unchanged squad on Monday for Lord's, with attention focused on whether fast bowler Steven Finn, not at his best in the second innings, would be retained in the starting XI for a match at his Middlesex home ground.
There were also concerns as to whether James Anderson, the fulcrum of England's attack, would be able to recover in time after a punishing first Test where he bowled 13 successive overs Sunday on his way to a decisive match haul of 10 wickets.
"It will have taken something out of all the players involved," said Flower of what he said was a "sensational game".
"But that's why our guys work so hard on their fitness and they are mentally resilient — they have shown that.
"Over a number of our Test campaigns, [they have] come out on top because of that resilience and I expect them to show that at Lord's in the second Test."
As well as praising Alastair Cook's "strength and calmness as a captain", Flower also highlighted the contributions of Anderson and Ian Bell, whose second innings 109 was the only century of the match, to England's victory.
"Jimmy Anderson, particularly, again showed his skill and class," he said.
"Ian Bell obviously showed real skill, but also, I think more importantly, a real determination and courage out there in the middle to bat like he did."
Meanwhile, Flower defended Stuart Broad over his refusal to walk during the second innings.
The all-rounder had edged a ball from debutant spinner Ashton Agar via wicketkeeper Brad Haddin's gloves to Australia captain Michael Clarke at slip.
Broad, on 37 out of his eventual 65 during a key partnership with Bell, stood his ground after experienced umpire Aleem Dar ruled he was not out.
It appeared a clear deflection to many with the naked eye and all the more so on video replay.
But as Australia had used up their two permitted innings challenges under the Decision Review System, they had no way of overturning Dar's verdict.
However, former Zimbabwe batsman Flower said: "Stuart Broad, like every other batsman in international cricket, has the right to wait for the umpire to make his decision.
"The umpire's job is to make those decisions."
He added: "I think that using the review system is the correct way for international cricket to go, because we get more decisions right using it."
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