Image source, Getty Images

Jordan Spieth rolls in for par to stay two behind Dustin Johnson, who is striding purposefully down the 10th fairway.

Up on 18 and Adam Scott takes a swish with his broom-handled putter. He's a good 80 feet from the hole and the ball zips past, slows up on a slope and dribbles back towards the cup. He has the birdie chance he wanted.

Six feet for three under and a terrific 64.

Australia's Adam Scott is five under for his round and two under for the tournament, playing the par-five 18th. One more birdie and that will be a challenging clubhouse lead.

His compatriot Jason Day has nine holes left. He takes iron off the tee at 10, a 460-yard par four, and finds the fairway.

Up on the green Jordan Spieth has a long look at a birdie but he doesn't hit it and he's left with a tester for par. Branden Grace from just off the edge nudges his ball close and that should be a par.

Jay Townsend
Former American professional golfer on BBC Radio 5 live

"This course will leave the players mentally exhausted. You have to think your way around every shot - how to use the slopes and terrain. You don't get a single shot off around here."

Image source, Getty Images

Shane Lowry goes way left off the 11th tee but he gets a huge stroke of luck. His ball comes to rest on a footpath and he takes full advantage, finding the green and there's a touch more luck as the ball catches a slope and meanders back to within six feet.

But that is where his luck runs out. His putt lips out and he is staying at level par.

Jordan Spieth two-putts for par. Can Jason Day get within two of the lead. No is the simple answer. And that is a big chance missed. Three-foot birdie putts do not come around often at Chambers Bay.

Jordan Spieth has tugged numerous drives today but his first shot on the 10th finds the fairway. He's not playing sparkling golf today but he's hanging around well.

Back on the ninth and Dustin Johnson's six-iron to the 203-yard par-three lands short and ends up 10 feet from the pin.

Jason Day goes the tried and tested way, firing long and letting the ball funnel back down off the slope. Day's way is better, he's got a three-footer for birdie.

Leighton Williams: If Dustin Johnson wins, is this not another nail in the coffin of all but the biggest hitters in golf? Sad if so.

Image source, Getty Images

Back on the eighth and Dustin Johnson lays up out of the rough. Good course management from the American who lazily flicks a wedge on to the green and gets it stop a couple of feet away. He's got that to get to six under.

Jason Day studies his putt with his caddie but between them they can do no better than get the ball eight feet from the cup. But then that's as close as they thought they could get the ball.

He marks his ball, cleans it, replaces it and strokes in for a birdie to get to three under. Johnson wastes no time in going two clear of Spieth and Grace.

Image source, Getty Images

Jordan Spieth and Branden Grace play the ninth perfectly. Sending the ball way past the flag, allowing the contours to feed it back towards the hole.

Spieth's trundles to the front edge and he'll have a 15-footer for birdie but he doesn't hit the putt. Grace's stops right next to the hole and he joins his playing partner on four under as they make the turn for home.

Image source, AP

A double fist pump from Shane Lowry. The Irishman bends in a 10-footer on 10 to get to level par. He looks like he's enjoying himself out there.

Jason Day from the middle of the fairway on the par-five eighth. His ball skips through to the back of the green and threatens to head off down the slope to the right of the green but decides to to give the Australian an eagle opportunity.

Brandt Snedeker is up to two under after an incredible run of four successive birdies to close out the front nine. The American started the day at one over and has just scrambled for a tremendous par on the 10th.

Chris Jones
BBC Radio 5 live commentator at Chambers Bay

"Brandt Snedeker is not out of this."

Image source, EPA

On the eighth green and Jordan Spieth has an eagle putt to move into a share of the lead. It misses but that's a tap-in birdie and the Masters champion is very much in this at four under.

Two-putt par for Branden Grace to stay three under. The South African also in the hunt.

Iain Carter
BBC golf correspondent on Radio 5 live

"McIlroy rather resignedly bends down and takes the ball from the hole. It was a fabulous effort and for a short while he threatened to really get in the mix, he threatened at one stage the lowest round in major history."

Image source, Getty Images

Dustin Johnson has a 12-footer for birdie on seven but he's not borrowed enough there but a tap-in par is welcome.

Jason Day is fighting hard. His second wedge into the green is hard enough to go eight feet past but he is not confident enough with his par putt and it goes the same way as his playing partner's did a few seconds earlier. He is back to two under.

Up on the 18th and the world number one is finishing up. He chipped out the bunker, got too much spin on his wedge approach and then shaved the hole with a 40-foot birdie putt.

Thanks for the charge Rory McIlroy. Fair brightened up the early part of today's final round. A four-under 66 and level for the tournament. He's the clubhouse leader for now.

Is it me or does Jason Gunn sound exactly like Graeme McDowell? It's that Americanisation of the Celtic accent..

Back on the course and Jason Day is a yard shot with his approach to the seventh green and that is rolling off the green, down the slope but mercifully it catches some rough to stop it running back 70 yards.

Scotsman Jimmy Gunn is currently tied for 29th at five over after carding a level-par 70 in his major championship debut.

He told BBC Radio 5 live: "It has been a great week. I actually played my best all week today. Two bad swings cost me but a good finish birdie-par-birdie so I can't complain.

"It has been great, especially to have my family here too. The USGA have looked after us amazingly well.

"It just reminds me once again that my game's good."

Image source, Getty Images

Rory McIlroy drives into the bunker on the par-five last. Hopes of an eagle two to get to two under evaporate in an instant.

Back on the 477-yard par-four dog-leg right seventh and Dustin Johnson clatters a three-wood over the bunkers to leave himself a wedge into the green.

Jason Day follows him with a similarly aggressive play and he too is in the fairway.

Jason Day blasts out of the sand to leave himself a six-footer for par. Dustin Johnson was long and left and his play out of the fescue grass stops 20 feet short but that's no bother to DJ who rolls in for par. A quick fist pump and the game face is back on.

Day from the other side and half the distance watches as his ball bobbles left and he is back to three under.

Johnson leads by two, again.

A huge sigh from the crowd (and me for that matter) as Rory McIlroy's par putt slides right past the hole on 17. It didn't even trouble the lip. A dropped shot and back to par. Game over.

Shane Lowry is also back at level but he has more momentum after his birdie putt on eight.

Matt Kuchar is suddenly up to one under after a birdie at 11 and an eagle at 12 after driving the par four green and finishing four feet from the pin.