A bogey at the third was the only hiccup on an otherwise pleasing scorecard for Casey who completed the second round with a total of 9-under; six strokes better than his overnight score.

“The last four was nice.  I’ve not been able to get it close to any flag for about a day and a half and then suddenly the back nine for me, the front nine, the last half a dozen holes, suddenly some really good birdie opportunities,” Casey said.

“I don’t know if it was fully in the zone but it was really nice stuff and it felt really good, so suddenly from a case of sort of bumbling around, just a couple under par, challenging for lead, and in the lead right now; so good stuff.”

After battling difficult, smoky conditions yesterday afternoon the benign morning that greeted the field was welcomed by Casey but the Englishman insists both settings played little part in his overall performance.

“I didn’t really change anything.  The strategy stayed the same, continued to hit very similar tee shots to the tee shots I hit yesterday,” he said.

“Still stuck in the bunker on the right on five; it always seems the same, but the outcome was different.  But that could be something as simple as I said yesterday, there are variables that do change, such as pin positions, and that was the case a little bit today.”

Low scores were there for the taking in the morning of round two where six players including Casey, Deyen Lawson, Cameron Tringale, Denzel Ieremia and Mark Brown posted best-of-the-day scores of 6-under the card.

Tringale’s efforts elevated the American up to a tie for second place alongside Louis Oosthuizen, Ieremia and Queensland’s Shae Wools-Cobb at 8-under.

Crowd favourite Adam Scott may have done just enough to progress to the weekend with a second round of 4-under.

After struggling through his opening 18 holes, Scott found his groove again following a morning range session that included an adjustment to his stance and swing, enabling him to crawl back from a 4-over overnight score to sit at even-par.

“I adjusted my posture this morning on the range and changed the path of my swing a little bit and it was a good move, because I was really struggling out there yesterday,” Scott said.

“It was better.  It wasn’t feeling amazing out there today, it was hard work, but definitely on the right path today.

“Hopefully I didn’t shoot myself in the foot with a bad round yesterday and I’d like to play two more rounds and keep working on this.  You never know, I can have a decent result here and then be in good form going into next week and the PGA.”

Following the second round a cut will be made to the top 60 players and ties. The cut currently stands at even par as the afternoon field takes to The Australian layout.

Overnight leader Chun-An Yu went enjoyed a quiet day on course for 1-under and a 7-under two-round total.

For live scores from The Australian Golf Club visit pga.org.au, follow @PGAofAustralia on Twitter or @pgatouraus on Instagram and use the hashtag #AusOpenGolf.