Rory McIlroy found consistency to be a fleeting commodity during a roller-coaster second round at the Australian Open but will still go into the weekend just one shot off leader Greg Chalmers in Sydney.
The defending champion had hoped to improve on his opening-day 69 after admitting he was struggling with jet-lag, but he ended up having to settle for the same score on Friday after an eventful 18 holes that included an eagle, six birdies and six bogeys.
The world number one, who was two shots off leader Jordan Spieth overnight, started off with successive pars but after that he only parred three of the next 16 holes as he struggled to build any momentum.
He dropped shots on the third, fourth - when he found water - and seventh, while recording birdies on the fifth and ninth as he reached the turn in a one-over-par 36.
McIlroy started the back nine with another par on the 10th, but that was his last of the round as he embarked on a remarkable mixed run of scoring that included four birdies, three more dropped shots and also an eagle on the par-five 14th.
The 25-year-old was left to wonder what might have been after the round, and told www.pga.org.au: "I felt like I had an opportunity today to maybe shoot a good one and put a little bit of space between myself and the rest of the field but it didn't really pan out that way.
"I had six birdies and an eagle today. You eliminate the bad stuff and the bogeys and all of a sudden you turn that into a low score.
"I was happy with how I finished obviously, I was four-under for the last five holes and came back well and still in a good position going into tomorrow."
All that left the Northern Irishman on four under for the tournament and in a four-way share of second place alongside Adam Crawford (69), amateur Todd Sinnott (67) and Conrad Shindler (68).
Australian Chalmers is setting the pace at the midway point on five under after following up his 71 with a 66 - including a birdie on the last which saw him claim the outright lead - while Spieth slipped back to three under after only managing a 72.
World number three Adam Scott, who was edged out by McIlroy on the 72nd hole last year, also carded a 66 as he bounced back in style from his 74 on day one to sit on two under par.