Adam Scott has made a disastrous start to the Australian Open, but world No.1 Rory McIlroy is safely in the clubhouse just one stroke off the lead.

McIlroy closed with a tap-in birdie to post a two-under-par 69 in cool and overcast conditions on Thursday at The Australian course in Sydney.

Scott, though, staggered to the turn at five over in his opening round after starting with a horror double-bogey six and then dropping further shots at the par-4 third, sixth and ninth holes.

While 33 players were in red figures midway through the first round, Scott was languishing in a share of 138th position and in serious danger of missing the halfway cut if he didn’t make major inroads over his next 27 holes.

Sydney’s born-and-bred Aron Price was setting the early pace after firing a first-round three-under 68.

Richard Green and Adam Crawford were with McIlroy in equal second spot after carding 69s.

Crawford had an eagle on the par-5 14th, as well as four birdies and four bogeys, but McIlroy’s round wasn’t anywhere near as eventful.

Starting his title defence from the 10th tee, the world No.1 turned in even par after notching just one birdie on his opening nine, at the 459-metre 14th.

He handed the shot straight back when unable to save par from the trap on the par-3 15th before collecting up-and-down birdies on the first and fifth holes – his 10th and 14th for the day – to climb to two under.

McIlroy again dropped a shot after finding the sand with his approach on the seventh but, after labouring most of the morning, the Northern Irishman stiffed an approach shot at the last to briefly grab a share of the clubhouse lead.

Playing alongside McIlroy, Matt Jones – a lifelong member of the course – struck a spectator in the head with an errant drive on the second-last hole.

There was concern for the fan, with medics called, but he appeared okay and received a signed ball from the US PGA Tour star, who refused to blame the incident for his late implosion in a disappointing round of 76.