A vital century by Steve Smith put Australia in a strong position and frustrated England in the third Ashes Test after they had threatened to bowl the hosts out cheaply on Friday.
Australia's fragile top order again stuttered as the hosts slumped to 143-5 on the first day, before Smith came to the rescue with his second Test ton in what could be the series decider.
At stumps Australia were 326-6 with Smith unbeaten on 103 and Mitchell Johnson on 39, further loosening England's grip on the trophy at 2-0 down and three to play.
Having turned the first two Tests with his fiery fast bowling, Johnson was threatening to inflict more pain on the English, this time with the bat.
Johnson had hit six boundaries as he and Smith added a quickfire 59 and counting for the seventh wicket.
Australia lead the five-Test series after big wins in Brisbane and Adelaide, and can secure the Ashes with victory in Perth.
But not for the first time in the series they found themselves in early trouble with the bat after winning the toss.
Playing his 100th Test, as was his English counterpart Alastair Cook, Australian captain Michael Clarke elected to bat on a sweltering day.