Local favourite Brett Rumford recorded a sparkling 65 to take a share of the 36-hole lead at the ISPS HANDA Perth International, but he will be looking over his shoulder at World Number 21 Louis Oosthuizen.
Perth native Rumford recorded eight birdies to join Peter Uihlein at the top of the leaderboard on 11 under, with Oosthuizen just a shot back after a scintillating round of 64.
The South African made five birdies in six holes from the 12th and had a short putt on the last to tie the course record at Lake Karrinyup Country Club but made a rare error and had to settle for second place.
Uihlein fired an impressive opening 65 in windy conditions on Thursday afternoon to hold the overnight lead and once again had to tackle the elements in a gutsy 68.
But when the wind dropped a little in the afternoon, it was Rumford and Oosthuizen who put on a show, with the local fans revelling in every birdie from the home favourite.
"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.
My concentration waned a little bit coming home but I made some nice up-and-downs and made some nice putts from long range as well so all-in-all I was really happy - Brett Rumford
"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."
The 38 year old missed a large chunk of last season after having 30 centimetres of small intestine removed but has made a steady start to the new campaign as he hunts for a sixth European Tour title.
A brilliant chip-in from the left of the sixth green had him three under for the day and when he birdied the 11th he was into double figures for the week. A pushed tee-shot on the 12th surrendered his only bogey of the day but he holed from 20 feet on the 14th and brilliantly got up-and-down from a bunker on the next to join Uihlein.
Earlier, the American had a birdie-birdie finish thanks to two lengthy putts to set the target as he showed no signs of the wrist injury which has troubled him recently.
Oosthuizen - the 2010 Open Championship winner - stole the show in the afternoon, making three early birdies before a run of seven straight pars, but he came to life on the 12th with a ten-foot birdie putt.
Huge drives helped him to further birdies on the 13th and 14th before he took advantage of the par five next to make it four in a row. A 30-foot putt on the 17th then got him into double figures before he missed a three-foot birdie effort on the last.
Australian Rhein Gibson was then at nine under following a 68, with countryman Jason Scrivener a further shot back thanks to a 67. Frenchman Alexander Levy also had a 67 to sit at seven under, a shot clear of Singapore's Mardan Mamat.