Australia captain Michael Clarke said he was "extremely disappointed" after his team suffered a 74-run defeat by England to go 3-0 down in the Ashes series with one Test to play.
Chasing 299 to win, the tourists looked well set on 168-2, but lost their last eight wickets for 56 runs to slump to 224 all out late on day four.
Clarke said: "It's extremely disappointing - it's hard to swallow.
"I guess I know now what it feels like to lose an Ashes series as a captain."
Australia were torn apart by a superb spell of bowling from Stuart Broad, who took 6-20 in 45 balls to wrap up a dramatic match at 1940 BST.
"Chasing nearly 300 in the last innings of a Test match is always going to be difficult," said Clarke.
"I don't think today was about forgetting how to win. I just think a good bowler got his back up and got some momentum and we couldn't stop him."
Despite his praise for Broad, Clarke was critical of Australia's batting after they were bowled out for 270 and 224 at Chester-le-Street, and did not exonerate himself from blame.
"I want our batters to get more runs," he said. "I'd like our batting to be stronger. Our bowlers are doing a fantastic job but I don't think we are making enough runs - it's as simple as that.
"I am part of the batting unit - I am no different to any other batter in that order. My job is first and foremost to score runs and I only made 25 in this Test and that's unacceptable."
However, Clarke remains confident that they can improve, starting with the fifth and final Test of the series at The Oval from 21 August.
"The fifth Test is as important as the first four have been. We have to play some good cricket and I think we have shown in patches that we can do that," he added.
"We have got the potential and the talent - if we play the brand of cricket we have shown glimpses of, then I am confident we can beat any team in the world."