Clarke insists that his team have the ability to bounce back and triumph in the five-match series but says they know far better performances will be required.
The Aussies arrived as favourites, having hammered England 5-0 in the last Ashes series, but they could not continue their dominance on the slower terrain of Cardiff.
The tourists found themselves on the back foot from the moment man of the match Joe Root completed a first-day century after being dropped on nought and England eventually prevailed by 169 runs in the final session of day four.
Clarke said: “To cut a long story short, I thought we were outplayed in all three facets of the game.
“England’s batting in the first innings, their bowling throughout the game, and their catching, was exceptional.
“I think England deserve a lot of credit and we have got some time now to prepare and get ready for the second Test match. We have got some work to do.
“I think the guys have prepared really well, we just haven’t played our best cricket. Against good opposition, if you don’t play your best, you lose.”
Brad Haddin’s crucial drop of Root was one key moment and it also proved critical that several top-order Australia batsmen failed to build on promising starts in their first innings.
And, although rain could be in the air on Sunday, the tourists’ failure to bat through Saturday means any bad weather will not be a factor.
Clarke added: “When you are playing against a very good team, if you get in, you have got to cash in. And, if you get an opportunity as a bowling and fielding unit, you have to hang on to those chances.
“We tried to play our natural game (on Saturday). Some guys looked to play positive, other guys backed their defence a little bit more.
“Whatever we tried today, it did not work, so we don’t have to worry about the rain tomorrow!”
Clarke says he expects the Australians to adapt to the slower wickets in England.
Asked if his team could bounce back, he said: “Most definitely. We know what is expected of us as individual players and we know the conditions.
“I think part of playing international cricket, you have got to have success away from home as well, and a big part of that is adapting to conditions.
“Let’s wait and see what the wicket is like at Lord’s. I look forward to hopefully seeing a bit more grass but, if we get similar conditions, we have got to play better than we did here.”
Key bowler Mitchell Starc took seven wickets in the match for Australia but appeared to be limping at times and could be a doubt for the second Test, which gets underway on Thursday.
“He walked out and batted, which is a positive,” said Clarke. “He was still able to bowl and took a couple of wickets in the second innings. Hopefully, he will be fit and available for selection for the second Test.
“I think the real positive for us is that he was able to bowl and get through it.”