Day takes aim with his second at 11, not much more than a wedge in his mitts... it's perfect length, he's got about 12 feet for eagle. Finau missed the fairway at 13 and pays the price, getting no grip. Casey just misses with his birdie attempt at the last and is in with a third successive 70 for six under.

Lahiri has reeled off birdie at 11 and 12, he's only two back. Day on tee at 11, going with the big stick and that's a doozy, a thousand yards down there and on the short stuff. Jones has found his driving boots, he's safely away. Spieth pops in for birdie on 13, he's two off the lead.

Norwich City striker Gary Hooper is watching...

Image source, Gary Hooper

And enjoying.

Finau showing big cojones with a great saver at 13, he stays in the lead on 12 under. Spieth could go 10 under, he's all over the flag with his approach at 13. This is some magnificent golf, we have hit the motherload at Whistling Straits.

Jones for birdie on 10, from about 25 feet... good pace, will pop in for par. Grace from the sand at 18... HOLED IT! Have that, that's a 64 for the South African and 12 under overall - we have a three-way tie for the lead. It's all going off out there - Day makes birdie on 10, makes it a four-way tie for the lead, before Rose misses a four-footer for eagle on 11. He moves to -11, when it should have been -12. Kaymer in with a 65 and -11.

Day and Jones both safely on in two at the 10th, Rose stiffs his second to within a few feet at 11 and he's got that for eagle and a share of the lead.

Spieth bends in another birdie on 12, he's now three off the lead. Kaymer with a peach of an approach at 18, he's got a putt for a 64. Finau on tee at the par-three 12th, 140 yards, yanks it left. Casey's par attempt at 17 doesn't break and he drops to -6. Grace in strife on 18...

Spieth has birdied 11 and is now only four off the lead, this is bubbling up very nicely indeed. And when you chuck someone playing shots out of a beer tent into the mix, it tastes even spicier. Finau has got a 10-footer for eagle at 11, doesn't hit it! But the 25-year-old American pops in for birdie and a share of the lead.

Image source, Getty Images

Dustin Johnson is not out of this yet, he's birdied the 14th to get to eight under. Day rams home his birdie putt at nine to get to within one shot of playing partner and fellow Aussie Jones.

Grace can only make par at 17, he stays 11 under and in a three-way tie for second. Jones with a 12-footer for par... skips over the cellophane bridge, that's only his second bogey of the week and he drops to -12, one clear of the field.

Image source, Getty Images

Meanwhile, Kaymer's on fire - the German bends in a monster on 17 to get to seven under for the day and 11 under for the week. Casey of England with a great saver at 16, he stays seven under. Day, by the way, was safely on in two at the ninth, by more conventional means than playing partner Jones.

Some suggestion that Jones is going to play it where it lies, someone is even taking a hanging basket down. From what I can work out, he's going to have to clear a picket fence which forms the perimeter of the booze tent that overlooks the ninth green. It's all getting a bit Van de Velde out there. Jones takes aim, clips his ball off the blue carpet with a thud, up go the screams and his ball ends up on the edge of the green. Lovely stuff.

Kaymer on tee at 17 and he's safely on. Here's Jones's ball, which has come to rest in front of the beer tent. It's a 70 yard hook and I'm not quite sure where Jones is going to drop it. Off he goes to find out, Aussie fans will be pleased to know he seems to find the whole situation quite amusing.

Branden Grace taps in for birdie on 16 and he joins Finau on 11 under, tied for second. Jones, all of a sudden, is looking a bit iffy - slice off tee at eight, he's now duck-hooked his drive at nine. That's gone straight into the hospitality tent and doesn't look like it's come out again.

Day and Jones both scramble for pars at eight. Rose has marmalised a three wood 340 yards off the tee at nine, some of these distances are mind-boggling. Kaymer for eagle at 16, doesn't borrow enough. However, the German moves to 10 under, three off the lead.

Rory McIlroy reacts to his mark of six under on Sky Sports: "I got off to the perfect start. I knew there were a couple of chances early on.

"I got on a run of bogeys and birdies from there but nice to finish with two birdies in the final three.

"I think I've shown improvement each and every day which is a great sign. especially going into the last stretch of the season.

"I didn't know how I was going to play this week so to come back in a major championship and give a good account of myself is great. I'd like to shoot something low tomorrow but it's not likely to be enough to win."

Rose on tee at nine and he whip-cracks one down the middle. Charl Schwartzel of South Africa is in with a 68, the former Masters champion is six under overall. Day at eight with another fine recovery, should save par. Jones cosies his birdie putt up towards the hole, he should stay -13.

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Day taking eight iron at eight - from 200 yards - and he misses the green long and left. Finau on nine and he bends in an eight-footer for birdie, he grabs outright second on 11 under. Jones finds the front of the green with his second, should make par from there. Kaymer on 16 and he's on in two, what a shot that was, he's got an eagle putt from about 25 feet.