Under-pressure England coach Eddie Jones has vowed his side won't let Australia "off the hook" again after his team's failure to win the first Test against a resilient 14-man Wallabies in Perth.
England were leading 14-9 with 20 minutes left on Saturday evening, but couldn't finish the job, losing 30-28 despite scoring two late tries.
The defeat leaves them facing a must-win clash in Brisbane this week to keep the three-match series alive.
"At 14-9 and with 20 minutes to go we should have put that game away and we didn't so we are very disappointed in that," said Jones, who is under mounting pressure after a disappointing Six Nations this year and then an embarrassing loss to the Barbarians ahead of Australia.
"But the commitment from the players now is that we have to win the series 2-1. We will learn from this game and make sure to not let them off the hook next time."
England went into the clash buoyed by winning all eight games against Australia since Jones took over, but they proved shapeless in attack and porous in defence.
Dave Rennie's side lost fly-half Quade Cooper to injury before kickoff, then fullback Tom Banks departed with a broken arm and prop Allan Alaalatoa followed him to the treatment room, all within the opening 25 minutes.
Lock Darcy Swain was then sent off in the 34th minute for a headbutt to leave the home side at a major disadvantage. But they rallied against the odds to come away with the win, leaving Jones with plenty to ponder.
"The message at half-time was to put more pressure on them and we did that in spurts but we let them off, two or three times we were on their line and we didn't finish the move off," he said.
"And contrary, when Australia got into our 22 they finished their movement off. We have to tidy up our ability to finish in attack and defensively we could have gone after them more."
- 'Absolutely rapt' -
Skipper Courtney Lawes said there were positives to take, notably two late tries from substitutes Henry Arundell and Jack van Poortvliet to ensure they have some momentum going into the second Test.
But he admitted their defence "wasn't good enough".
"We've got no end of strong players, so plenty of good things to come. The main thing for us is to focus on our discipline and defence," he said.
In contrast, the Wallabies will take huge confidence from the win with Rennie "absolutely rapt".
"Obviously we lost Quade before the whistle, Allan and Banksie and a red card to Darcy, but I think things were calm in the change room and we had a plan," he said.
"I thought the leadership on the run with a player missing was excellent and we showed a lot of character."
Banks is expected to miss the rest of the season, while Alaalatoa will miss the second Test due to the new concussion laws as Cooper races the clock to be ready for Brisbane.
Rennie suggested Australia may contest Swain's red card, keen to have him for the rest of the series with the lock a key lineout caller.
"If it's a headbutt it's a clear red card but I don't think his intent was to headbutt him," he said. "We'll look at the footage and get clarity about whether there is an opportunity to challenge."