World No. 1 Jordan Speith confessed to a ‘brain fart’ at the final hole during the first round in the defence of his Australian Open title in the testing hot but very windy conditions in Sydney.

Spetih recorded three birdies and an equal number of bogeys in a level par 71 on the Australian Club course.

It left the double Major winning Texan trailing five shots behind Australia’s Lincoln Tighe who enjoyed a two stroke clubhouse lead with a five under par 66.

Double Major winning Jordan Speith mobbed as he heads to the scorer’s hut.

Tighe, who is the reigning New South Wales PGA champion and is into the final stage of qualifying next month for the PGA Tour’s secondary Web.com Tour, leads former Australian Open winner Geoff Ogilvy and Taiwan amateur Chun-An Yu.

Speith commenced his round with a birdie and indicating it to be the highlight of his round in birding the 10^th or the first hole of his round.  He then moved to two under par with a birdie at his fifth hole but dropped a shot at the next before getting back to two under par a birdie at his ninth.

The 22-year double Major winner then bogeyed his 13^th and final holes where he pulled the wrong club to leave his second shot well short of the green.

Jordan Speith signing autographs after his round of 71.

“It was difficult out there as we played a lot of holes in side-winds, so it was just a guessing game ​and moreso when you bring hazards into play,​” he said.

“It’s been a while since I’ve played in wind like this and with the toughest part in deciding what shot to hit. You can use the same club and end up with a 30-yard difference based on if you hold the ball up or ride the wind.

And there was no better example than at the par-4 ninth hole and the 18^th of his round where Speith’s second shot was a good 10-yards short of the putting surface.

Speith again mobbed as he heads to the clubhouse following his round of 71.

“That last hole was really tough as I just didn’t know what to hit and I ended up two clubs off, thinking the wind was helping when it was actually hurting,” he said.

“Lee (Westwood) and Geoff (Ogilvy) had the some trouble. We just had no idea. But I still should have made par.

“If you give me 100 balls, I’ll get down in two 95 times from where I was. It was a brain-fart there.”

Tighe has only just returned to Australia after qualifying early next month for the final stage of the Web.com Tour School.

It is his second Australian Open appearance after missing the cut a year ago.

“I am very pleased as I have always loved the Australian Club as it seems to set up so well for me, so I am not surprised as my game has been good for some time now.

“And this round is good timing as I head back to the States on December 7^th for the final round of qualifying for the Web.com Tour.

“I am already assured my card but then if I manage to finish top-45 you get a full Tour card.”