Third Ashes Test, Perth (day three, close): Australia 268 & 309 v England 187 & 81-5 Venue: Waca Date: 16-20 December. Play resumes 0230 GMT on 19 Dec Coverage: Live on Test Match Special on BBC Radio 4 LW, 5 live sports extra and online; live highlights and day's review on the
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Would England play another seamer alongside Tremlett, Anderson and Finn?
By Jonathan Agnew
BBC cricket correspondent in Perth
After the euphoria when England saved the Test in Brisbane and their emphatic win in Adelaide, an inevitable Australia victory here in Perth means the Ashes is set for a phenomenal finale.
The Waca is a one-off, unlike any ground around the world. It's a venue Australia have made their own - England have won only once in 11 matches, and that was against an Australian side weakened by the World Series defections in the late 1970s.
England have not become a poor team overnight, but a number of poorly judged shots in the second innings - Kevin Pietersen and Jonathan Trott in particular - have not helped their cause.
However, a lot of praise must be heaped on Mitchell Johnson, who has once again bowled with pace and fire, and at times has been very nasty to face on what has been a lively pitch.
Johnson's success in Perth may well force Australia to review their strategy and adopt a four-man pace attack for both Melbourne and Sydney.
The Waca pitch has benefited Johnson, who plays his Sheffield Shield cricket for Western Australia, and we could well see more grass left on the wickets at the MCG on Boxing Day and at the SCG for the New Year Test.
This particular tactic works two-fold in Australia's favour. One, the hosts believe England's batting line-up are uncomfortable against short-pitched fast bowling, exemplified by their collapse against South Africa in Johannesburg at the start of the year.
And two, it would force England to review their tactic of playing three seamers alongside Graeme Swann for the remainder of the series.
The spinner had plenty of assistance in Adelaide, with rough outside off stump for both the left and right-handers on a dry, cracking pitch.
But here in Perth, Swann has had almost nothing to work with, which was reflected by second-innings figures of 0-51 from nine overs. Mike Hussey, in particular, played him beautifully, using his feet as he has done all throughout this series to get to the pitch of the ball.
So if England find themselves up against another grassy, seam-friendly pitch, can they go into back-to-back Test matches with only three front-line fast bowlers?
Sydney is traditionally the Australian ground most receptive to spin but SCG groundsman Tom Parker has been preparing grassier wickets for New South Wales' Sheffield Shield matches, so it can be done.
England's Chris Tremlett looks for positives
But would England drop Swann, the world's best spinner, from their line-up?
Watching the morning session, I was disappointed to see Andrew Strauss set a 7-2 off-side field when James Anderson was bowling to Shane Watson.
The ball was still swinging but with a field like that, you can't bowl straight because anything on middle stump will be worked away to the legside.
Watson is an lbw candidate, as his first-innings dismissal suggested, but because of the off-side heavy field, Anderson's line was off stump and outside, enabling the Australia opener to shoulder arms to a number of deliveries.
I understand England didn't want Australia to get off to a flyer, but I would liked to have seen England on the attack, moving a man from the offside into the legside and enabling Anderson to bowl a middle and off-stump line.
Instead the tactics were a little too negative for my liking as England's seamers wasted a lot of precious energy on deliveries which Australia's batsmen left without trouble.
Once again Hussey batted beautifully with superb judgement on the ground where he has played the majority of his cricket.
He became the first player in history to score 50 runs or more in six successive Ashes Test matches by choosing which deliveries to leave and which to dispatch to the boundary.
The Waca is a tough place for the east-coast Australians too - only Shane Watson has managed a decent innings from the non-Western Australia players in the team.
England's top order could learn from Hussey's astute judgement.
Jonathan Agnew was speaking to BBC Sport's Pranav Soneji.
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