Ashes - How Australia are taking key wickets by design

While England's batsmen can fairly be accused of frittering away their wickets on this Ashes tour, the first innings of the third test in Perth has proved just how much credit needs to go Australia slipper Michael Clarke and his bowlers.

Starved of scoring shots through their favoured areas, England's batsmen were forced to take risks in an attempt to accelerate the scoring rate and put some pressure on the hosts.

Australia found scoring much easier against England's bowlers - Friday's score of 326 was the highest first-day total ever at the WACA and they added another 59 to be all out for 385 on Saturday.

England's batsmen have scored at a run-an-over less than Australia's - 2.64 to Australia's 3.71 - and limped to stumps on Friday at 180-4.

Michael Carberry, who played on for 43 to break up his 85-run opening partnership with captain Alastair Cook on Friday, said England's batting woes had been a combination of good Australian bowling and poor shot selection.

"The pressure has brought about some bad decisions at times, and bad shot selection," he told reporters.

"Having said that, in this innings I thought we've picked and choosed when we've gone hard at certain deliveries which I think is the right way to go."

The dismissals of both Cook and England's main attacking threat Kevin Pietersen after tea on Friday were perfect examples of Australia's careful planning bearing fruit.

Australia dismissed Cook by focusing on his insecurities at playing through the offside.

The metronomic accuracy of Australia's attack allowed captain Clarke to place to men on the leg side cutting off two of Cook's favourite shots - the clip off the pads through square leg and the drive through mid-wicket.

With the bowlers bowling a full length and not feeding Cook's favoured cut off the back foot backward of square through the offside, Clarke was asking Cook to either play his least favoured extra-cover drive or defensively.

Cook's strike rate of 47.05 -- none of Australia's batsmen had a strike rate of less than 50 -- bore testament to the fact that he chose caution over bravado.

So when Clarke brought the off-spinner Nathan Lyon back on, Cook felt compelled to seize the initiative.

The result: Cook perished on the fourth ball of Lyon's over to a fairly ordinary delivery.

"(Our) bowlers are getting vital wickets at vital times and Nathan Lyon did that today, everyone's chipping in," Australia bowling coach Craig McDermott told reporters.

Pietersen suffered a similar fate.

Starved of anything full to drive through the offside and two men placed at mid-wicket to stop him whipping the ball square through the onside, he cut a frustrated figure.

Short balls were employed to intimidate him and there was no width to cut, while back of a length bowling was used to force him into driving uncomfortably on the up as the ball was rising.

That resulted in Pietersen scoring just 19 off 59 balls - a strike rate of just 32.20 - and eventually his patience snapped.

With his captain back in the pavilion Pietersen felt he needed to take the attack to the Australian bowlers but he lost his wicket just 19 balls after Cook, trying to hit Peter Siddle on the up back over mid-on's head.

It was the tenth time Siddle had dismissed him in tests.

"Siddle just bowls very tight lines to Pietersen and (shows) patience," McDermott added.

"Pietersen was four off forty balls and digging himself a deep hole from my perspective and then he started hitting a run a ball.

"Siddle's tied him down time and time again and then the release valve comes and Siddle cracks him open."