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Back on the tee and defending champion Martin Kaymer of Germany finds the fairway. He is starting at two over. That's the same as playing partner Rory McIlroy who goes down the left edge and his ball snags in the cabbage. He may struggle to get up in two from there.

On the first, Sergio Garcia asks his ball to go right and it obliges, staying away from the nasty slope that has taken many a ball way down left of the green. He has a monster putt of what must be approaching 100 feet. Adam Scott goes further right and is rewarded as the ball bounds down off the hill to 40 feet shy.

Dustin Johnson is also imploring his ball to stay right. It doesn't and skips down were many before have gone.

The completely unique swing of 2003 US Open champion Jim Furyk sends his ball careering down the 10th fairway. He is followed by Miguel Angel Jimenez and Colin Montgomerie. The 51-year-old Scot rolled back the years on Thursday to card a one-under 69. Another one of those today will do very nicely thank you. He is safely down the middle.

Brandt Snedeker, playing with Stenson, comes in from the right of the green and his ball curls to a stop eight feet the other side of the hole.

Over on the first, which is playing as a par five today, Matt Kuchar flips a wedge onto the green and he's got a 20-footer for birdie. He misses it but has a straightforward one to stay three under.

On the 12th, Mickelson comes up 20 feet short with a putt from the off the front of the green.

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Over on the 10th the other co-leader, Sweden's Henrik Stenson, is also away with a drive to the fairway and his second on the par four skips 10 yards past the hole and up a little slope which returns the ball to within 10 feet of the flag. Big birdie chance first up.

Joint leader Dustin Johnson gets his second round under way and he's a little fortunate not to find a fairway bunker. Playing partners Adam Scott and Sergio Garcia are also cleanly away.

Back on the 11th and both Mickelson and Bubba leave their birdie attempts on the green. Tap-in pars and off to the 12th tee we go.

Here's our joint leader Jordan Spieth on his round: "Two under each day is a goal that I want to do. My putter was on today, my driver wasn't but when your putter is on you can salvage a round. This is golf's toughest mental test. It's about testing patience. If my putter continues to stay hot we'll be in good shape."

At least Tiger will not be last. At the moment, that dubious honour belongs to 2011 Open champion Darren Clarke. The Northern Irishman had a 10-over-par 80 on Friday to finish +17.

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We skip back to the ninth to see the end of Tiger's round and it's an untidy finish. A snaking 40-footer slides four feet by and the par putt lips out. It's another bogey for the world number 195 and he ends with a six-over 76 and +16 for the tournament. And that folks, is the end of his involvement in this tournament.

Back on the ninth, Justin Rose two-putts for par and the Englishman is signing for a level-par 70 - that triple bogey seven on the seventh being his downfall. Still at two over for the tournament, he's far from out of this.

Back on the second and Phil Mickelson finds the green with his second shot but he's got a 30-footer for birdie. Playing partner Bubba Watson follows Phil's line out right of the flag and his ball picks up more pace off the hill and he's left with a more makeable dozen feet for birdie.

-5 Spieth (US) F, D Johnson (US) Stenson (Swe) -4 Grace (SA) F, Martin (US) 17, Reed (US). -3: Luiten (Ned) F, Finau (US) F, Summerhays (US) F, Kuchar (US)

Selected others +1 P Casey (Eng) F: +2 Westwood (Eng) F; Rose (Eng) F; +4 Donald (Eng) F +5 Poulter (Eng) 17 +15 Woods (US) 17

Projected cut: +5

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Peter Scrivener here to take you through the next couple of hours.

And I start on the 10th hole with Phil Mickelson immediately dropping back to level par. A poor second shot that missed the green proves costly, although Lefty's short par putt looked makeable. He's got 17 holes left to make inroads into the lead.

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Jordan Spieth's putting today deserves a slice of lead pie and that is exactly what he is getting.

He drains from eight to 10 feet on the final green of his round. That takes him to five under and back to the top of the leaderboard, alongside Henrik Stenson and Dustin Johnson who are yet to start their day's work.

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Jason Day is wobbling like he has taken a uppercut on the chin. Or sunk 12 Saturday-night pints.

I'm not surprised the Australians' vertigo was triggered as he made his way down from the crow's nest of tee down to the ninth green far below. It is really steep.

He regains his footing to splash out of the sand to within ten feet. Par putt next. A little shakily, it slips by. Four feet for bogey. In she goes and he is done at two under.

Lee Westwood has signed off on his round in very ugly style.

A triple bogey seven on the 18th leaves him the wrong side of par on two over.

Shame. A damn shame.

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Day's collapse came right in front of the grandstand on the ninth. Jordan Spieth shows some nice empathy, telling some rubber-necking spectators to put away their camera phones.

Spieth has hit a nice approach by the way and has a birdie chance.

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We have a problem out on the ninth.

Jason Day is in a crumpled heap on the fairway. It looks like he has collapsed rather than fallen. He suffers from vertigo and that is being pinned as the likely cause.

Medical attention has reached him already and he is sitting up and talking with the doctors.

Two things to mention as Phil Mickelson, Bubba Watson and Angel Cabrera tee off together.

First, someone shouts "get in the hole" on a par-five opener like a trained gibbon.

Second, the announcer practically gives Mickelson and Watson's zip codes, namechecking their home town and state. Cabrera is just "from Argentina". A chance to impart a much-needed geography lesson missed.

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Branden Grace has a real ogre of putt to contend with on the last. This is for par. It draws round, but not enough.

He makes the four-footer coming back to clock off with a three-under round for the day, four-under overall.

Our leaderboard is almost back to as you were. Overnight top dogs Dustin Johnson and Henrik Stenson have just Ben Martin for company.