Former champion Hinako Shibuno set an imposing clubhouse target on day one of the AIG Women’s Open at Muirfield.

Shibuno, who won her maiden major title at Woburn in 2019, made a flying start with birdies on the first three holes and went on to card eight in total in a six-under-par 65 in the £6million event.

That gave the 23-year-old from Japan a one-shot lead over American Jessica Korda, with Scotland’s Louise Duncan another stroke back following a 67.

Playing in the first group at 6.30am alongside former champion and local resident Catriona Matthew, Duncan recorded an eagle, four birdies and two bogeys to match her score from the opening round at Carnoustie 12 months ago, when she finished 10th while still an amateur.

“It was worth the 4.30 alarm,” said the 22-year-old, who turned professional in July and missed the cut in her first event in the paid ranks last week. “I wouldn’t be happy if it wasn’t worth it.

“I’m just really happy overall with my game. I hit loads of greens, lots of great putts. I stayed patient as well which led to holing a putt (for eagle) on 17.

“I think the key is I didn’t take it too seriously. I just went out and enjoyed my warm-up, had a wee chat with Dean (Robertson, her coach and caddie).

“I haven’t had a paycheck and still feel like I’m an amateur. Yeah, I’m rolling with the punches and we’ll see where it takes me.”

Two-time Solheim Cup captain Matthew struggled to a five-over-par 76, making double bogeys on the first and 10th and failing to make a single birdie.

“Being the first women’s pro event to be played here, it’s great, and me being local it was a huge honour to hit the first tee shot,” said Matthew, who lives in nearby North Berwick.

“Apart from the two doubles I actually played quite well. It’s a little frustrating. Louise played great though. Great round from her. She kept it very steady, didn’t get into any trouble and took advantage of the par fives.”

England’s Georgia Hall, who won the title at Royal Lytham in 2018, lies five shots off the pace following an opening 70.