England battle to 175-4 at tea in must-win third Ashes Test
Australia captured two more wickets in an enthralling middle session to leave England battling on 175 for four at tea on day one of the third Test in Perth on Thursday.
Opener Mark Stoneman scored his second half-century of the series on a sublime day at the WACA but was removed by paceman Mitchell Starc for 56 after England captain Joe Root was caught behind for 20.
Dawid Malan survived a stiff pace examination to be 42 not out, with wicketkeeper Jonny Bairstow on 14.
England, who batted first after Root won the toss, resumed on 91 for two after lunch, with the skipper on one and Stoneman on the cusp of his third Test half-century.
The Durham opener was nearly caught behind slashing at a wider delivery off Josh Hazlewood in the first over after the break but brought up his fifty on the next delivery, another full-blooded stroke sailing high over backward point for four.
It also brought England's 100th run of the innings but the tourists were soon under huge pressure.
Stoneman was reprieved on 52 twice, first when he nicked behind off Hazlewood only for the recalled Mitchell Marsh to miss the simplest of chances at first slip, the ball bursting through his hands and smacking him on his sunglasses.
On the second, a diving Nathan Lyon was unable to complete a difficult low chance at point when Stoneman fended away another Hazlewood short ball.
On the previous ball, the opener had been struck on the helmet by a rising Hazlewood delivery and needed several minutes to collect himself under the attention of trainers.
Root was out softly in the following over, caught down the legside by wicketkeeper Tim Paine, and Stoneman soon followed, though in controversial circumstances.
Paine leapt high to take a fine one-handed catch after Starc appeared to graze Stoneman's right glove but the caught behind appeal was turned down.
Australia reviewed and third umpire Aleem Dar over-ruled Marais Erasmus on the strength of a noise picked up on the 'snicko' technology.
Root was irked by the call and punched England's dressing room door in frustration.
Earlier in the day, Alastair Cook's 150th Test started sourly, the 32-year-old opener lasting just 16 balls before being trapped lbw by Starc.
Stoneman and number three James Vince put on a 63-run partnership before Hazlewood had Vince caught behind for 25 late in the morning session.
Day one at the WACA was overshadowed by spot-fixing allegations in a British newspaper.
The ICC said it took the accusations "seriously" but said there was no evidence to implicate any of the match's players or officials.
Australia lead the five-match series 2-0 and can win back the coveted urn with victory at the WACA.