Jason Day will need to rely on the sort of major collapse that once befell his fellow Queenslanders Greg Norman and Adam Scott if he's to become British Open champion.

Day battled and scrambled his way round Royal Liverpool on Saturday with a performance of considerable grit to keep himself in the hunt for another major triumph.

But like the rest of the Hoylake field, the former world No.1, looking to add to his 2015 PGA success, appears to be scrapping for second as US leader Brian Harman enters the final round five shots clear.

All the contenders can hope is that 36-year-old Harman will lose his nerve in Sunday's final round just as Norman famously did at the 1996 Masters, blowing an overnight six-shot lead to let in Nick Faldo.

Scott had a similar meltdown at the 2012 Open at Lytham, squandering a four-shot advantage and carding four successive last-round bogeys to gift-wrap the Claret Jug for Ernie Els.

On a Saturday afternoon when champion Cameron Smith effectively conceded his chances of back-to-back wins was over, and Min Woo Lee's challenge faded despite a late charge, Australia's hopes are down to a rejuvenated 'J Day', who's tied for fourth, seven behind following his two-under 69.

The 35-year-old from Beaudesert birdied three of his first five holes, holing from 32 feet at the fifth to offset a careless bogey at the third.

And when he found more inspiration at the ninth, missing the green but then putting up from the fringe to hole from 25 feet, he was suddenly joint-second.

But gritty perspiration rather than inspiration was largely the order of the day as Day made gutsy up-and-downs to maintain momentum.

A mishap eventually came at the 14th, when he hit a 50-foot uphill putt too softly, the ball rolling all the way back to his feet.

Putting well but missing by fractions, he was the picture of frustration when he narrowly missed another lengthy birdie attempt at the final hole.

Even though, at five under, he's only two behind second-placed Cameron Young, a clearly frustrated Day declined all post-round interviews.

After Thursday's opening round, he'd done the same; sweeping off to the range straight away to work on his game.

Lee, who'd started the day at three under alongside Day in a tie for fourth, failed to launch a challenge; dropping three shots in his first six holes.

He eventually did hole for successive birdies at the 15th and 16th to end at two under par, 10 shots off the pace.

"Didn't have it all day," Lee said.

"Slow start, just bad. Put it in a couple of bunkers and made some soft bogeys. (It) wasn't pretty."

The 24-year-old was cheered around the course by his double-major-winning sister Minjee Lee, but even she couldn't inspire him.

"I saw her a couple times, it was good to have her out here," Lee said.

"I feel like I'm out of the question (of catching Harman), so I've got to shoot a really, really low score tomorrow, and that's doable."

Smith's slim chances also evaporated.

Despite a three-under 68 pushing him to one under for the tournament, he admitted to feeling a little frustrated at being tied for 24th.

"Still probably a little bit too far back," he said.

Scott, who's three over, had earlier finished with an even-par 71.