Brett Rumford joined Peter Uihlein at the top of the leaderboard in his home city following a scintillating seven-under second round of 65, while Louis Oosthuizen made an ominous charge at the Perth International on Friday.
Rumford has not won on the European Tour since 2013, but the 38-year-old will head into the weekend with high hopes of ending his wait for another title after surging to 11 under.
The 38-year-old went round in 68 on Thursday, but took his game up a gear a day later at the Lake Karrinyup Country Club to move level with Uihlein, who held a one-shot advantage after the first round.
Rumford, absent for much of last season after having a section of his small intestine removed, made five birdies on the front nine and another three on the stretch, with his only bogey coming at the par-three 12th on a day in which windy conditions played a part.
"It was tough, it was really tough," said Rumford. "The wind was fairly benign when we started then it started to pick up about the tenth which certainly made things interesting on the back nine.
"It was just one of those days where you had to keep grinding, concentration had to be premium, and that's the kind of pressure this golf course puts on you."
American Uihlein followed up his opening 65 with a four-under 68 in challenging conditions.
The overnight leader made six birdies - including each of the last two holes - but bogeyed the 16th and the second after starting on the back nine.
Pre-tournament favourite Oosthuizen put on a show in the afternoon to propel himself into third place with a dazzling eight-under 64 and would have had tied the course record but for a mistake on the last.
The South Africa looked set to join Uihlein and Rumford on 11 under when he stood over a short birdie putt at 18, but failed to end a magnificent round on a high note after reeling off four birdies in a row from the 12th and making eight gains in total.
Australian duo Rhein Gibson and Jason Scrivener are well poised on nine and eight under respectively.