In a field featuring world number one and defending champion Jordan Spieth, it was unheralded IAS Graduate Lincoln Tighe who stole the show in the opening round of the Australian Open on Thursday. Tighe’s round of five-under (66) launched him to a shock one shot lead in the clubhouse at The Australian Golf Club in Sydney. The clean-hitting right hander leads fellow New South Welshman Matt Jones by a stroke. Spieth and the 2013 US Masters champ Adam Scott are both finished at even par. “It’s unreal. I wish I finished at six [under], but if someone said to me at the start of the day you’re going to be under par in these conditions I would have taken it,” Tighe told Fairfax Media. “To shoot five [under] and play solid was great. I’ll stick to my process and routine and whatever happens happens.” Tighe, 26, recorded seven birdies as he compiled his first round lead in the second of Australia’s three major tournaments. He credited playing several previous rounds at the course as a key factor to his career defining performance. ‘‘I played here last year and had a couple of good first two rounds but before this, I’ve always loved this course,” Tighe told AAP. ‘‘We used to play a one-day amateur tournament here that was big and I’ve always loved this place, probably because it suits me down to the ground. ‘‘I know I can carry a lot of the bunkers off the tee. If I’m hitting it good, it’s rewarding.”