Three-time major runner-up Jason Day has awoken from his slumber to charge up the leaderboard on moving day at the Australian Open at Royal Sydney.

Starting the third round at even par for the championship, Day peeled off eight birdies in a sparkling six-under-par 66 to give himself an outside shot at lifting the Stonehaven Cup on Sunday.

Day is the clubhouse leader at six-under overall, still six adrift of halfway leader Adam Scott, who was teeing off on Saturday afternoon with a two-stroke advantage over Irish drawcard Rory McIlroy.

The individual winner at last week’s World Cup of Golf at Royal Melbourne, Day said he struggled with fatigue over the opening two rounds of the Open but woke up feeling revitalised on Saturday morning.

He also had about an hour’s work on his back on Friday night after complaining from stiffness after his second-round 74.

“The energy from today compared to the last two days was much better,” Day said.

“The first two days I was just really tired, just wasn’t mentally sharp and just didn’t have my best stuff.

“Today was just much better. The swing felt like I was swinging a lot faster without even trying.”

Teenage amateur Ryan Ruffels also got to six-under late in his second round, only to stumble with a double-bogey five on the par-3 17th to slip back outside the top 10.

The 15-year-old nevertheless signed off for an impressive 68 to be four-under for the tournament and on track for a big finish in his Open debut.

In a promoter’s dream, Scott is paired with McIlroy for the third round and the Northern Irish superstar was vowing to continue to take up the fight to Scott after roaring into contention with a brilliant 10-birdie, seven-under-par 65 on Friday.

“I’m within striking distance going into the weekend. I feel like I can shoot a couple more scores similar to today and have a great chance,” he said after his second round.