He only had five pars on his card but defending champion Rory McIlroy is lurking ominously just a stroke behind two time champion Greg Chalmers at the Emirates Australian Open. 

McIlroy believes it will be tight in the final round on Sunday but he's confident he can find a low round over the weekend after making 10 birdies and an eagle in successive rounds of two under 69 at The Australian Golf Club in Sydney

At four under, he's in a four-way tie for second place with American Conrad Schindler and Australians Adam Crawford and amateur Todd Sinnott on four-under after a rollercoaster second round that saw him make just one par on the back nine.

“I felt like I had an opportunity today to shoot a good one and put a little bit of space between myself and the rest of the field but it didn’t really turn out that way,” McIlroy said after a round featuring an eagle, six birdies and six bogeys.

“A few too many mistakes and it was pretty tricky out there to be honest. Swirling quite a bit, which made it hard for club selection. Misjudged a few wedge shots and made bogeys from those.

“I was happy with how I finished, picked up shots in four of the last five holes and I’m still in a good position heading into tomorrow.”

The world No 1 found water twice in a one over par front nine, flaring his tee shot at the par-three fourth into the pond and then spinning a lob wedge off the right side of the narrow seventh green and into a watery grave. 

A long range birdie at the ninth gave him some momentum but his par at the 10th was his last of the day as he followed a two at the short 11th with bogeys at the 12th and 13th, an eagle three at the 14th followed by a birdie-bogey-birdie-birdie finish.

Chalmers, the 1998 and 2011 Open champion, birdied the last from 35 feet to shoot a 66 and lead on five under.

The 41 year old, who now has only conditional status on the PGA Tour after a poor year, did not have the best build up to the week.

He flew from his US base in Dallas to Perth for the Perth International and then on to Malaysia for a PGA Tour event before heading back to Dallas via London.

He then played on the PGA Tour in Mississippi, flew back to Dallas and headed on to Mexico for the OHL Classic at Mayakoba before returning to Australian for the Australian Masters in Melbourne.

"I don't feel jet lagged, (but) it's just my sixth event in a row and I'm trying to conserve my energy and ironically, the more birdies I make, it seems to be the more energy I have, so that's always a good thing," said Chalmers, who has had just 50 putts so far.

American Jordan Spieth shot a one over 72 and shares sixth with Geoff Drakeford and Brett Rumford on three under with world No 2 Adam Scott a shot further back.

“It was a struggle, big time struggle,” Spieth said. “I wasn’t hitting it well. If I wasn’t putting well I may have shot 45 on the back nine.”

Scott was five over after nine holes on Thursday but now appears to be right back in the tournament.

“We had a good morning for it, so I had to take advantage just for the sake of getting back in the tournament,” Scott said. "Sometimes you can say your game's in good shape and it actually is even though the score doesn't reflect that and I feel like I'm playing really well. 

"I'm struggling to get momentum going my way this week and last week and staying patient and staying calm certainly is a big thing in my game, paired with that kind of belief that if I just keep aiming where I want to hit it I'm eventually going to hit it there and I'll eventually make a putt if I keep just doing the same things over and over again, just like I do in practice.

"That's kind of how I feel. I certainly don't want to panic at that point when I'm 5-over after 9.'

Pipped by McIlroy on the 72nd hole last year, Scott was under pressure after opening with a three over 74 but he took advantage of benign early conditions to carded a bogey free 66 tha leaves him just three behind on two under.