Leader: -7 Mickelson
Kiawah Island's Ocean Course is longest in major championship history
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Laird -1 (10)
Scotland's Martin Laird is hanging around the top 10. After bogeying the first, he had a run of five pars before knocking in a birdie on the par-five seventh.
Three more pars have followed and he's in a decent spot. Just needs to sink a couple more putts to be right in the mixer.
Koepka -4, Grace -3 (6)
Well there's a collectors item for you! Brooks Koepka missing a tiddler for par - OK so tiddler might be a bit of a stretch but it's just three feet and he bangs it through the break and gets the dreaded horse shoe as it takes a look inside the hole but pops out.
Bogey for Koepka and he drops to four under.
It's bogey-birdie-bogey for Grace who throws another shot away with a missed green and then devlishily difficult chip back on that results in a two putt and bogey five.
Poulter +2 (11)
Is Ian Poulter's putter starting to warm up? He drops one in from 20 feet for birdie on the 11th.
This is a gutsy response to his earlier troubles.
Bezuidenhout -1, Matsuyama -4 (6)
Only a par for Hideki Matsuyama on six. He gave himself a chance though just coming up short from downtown.
Mickelson -7, Oosthuizen -4 (5)
Phil Mickelson won his first PGA Tour as an amateur at the Northern Telecom Open in January 1991.
Later that year, Kiawah Island hosted the Ryder Cup as the War by the Shore played out on the Atlantic coast.
Can he add his 45th PGA title 30 years on? The 50-year-old rattles in another par to stay two clear.
That brush with the drone hasn't put Phil Mickelson off though...
Image source, Getty Images-1 Casey
Not for the first time today, Paul Casey is scratching his head. How did that just happen?
A brilliant tee shot to six feet set him up with a superb birdie chance and from there well...it's a hole to forget for the Englishman.
He slides his first putt four feet past the cup and then takes two more to end up with a bogey. Absolutely dreadful.
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-7 Mickelson
-5 Koepka
-4 Matsuyama, Grace, Oosthuizen
-3 Grace, Streelman
-2 Finau, Zalatoris, DeChambeau, Casey, Woodland
Selected others
-1 Fitzpatrick, Laird
E Spieth, Fowler, Hovland
+1 Lowry, Harrington
+2 Poulter, Westwood
+4 MacIntyre, Rose, Hatton
+5 McIlroy
Koepka -5, Grace -4 (5)
Oh this is just glorious from both men as they’re throwing darts at the par-three fifth – 190-odd yards into the breeze and they’ve nailed their tee shots.
22 feet proves no problem for Grace, who strikes back immediately after that disappointing three-putt bogey on the last, with Koepka following him in from 11 feet to move to five under.
Here comes Brooks!
Mickelson -7, Oosthuizen -4 (4)
Mickelson wiggles his feet into the sand and sets up for one of those trademark bunkers shots, but it doesn't quite have the pace he'd like on it. Still around seven feet to make up to save par here.
No problem. Right into the heart of the cup and he stays at seven under par.
Louis Oosthuizen has work on to save his par too, but does from a similar length. Good stuff.
Koepka -4, Grace -3 (4)
A three putt for Grace results in a bogey five and that'll be hugely annoying for the South African after being on the green in regulation.
Poulter +3 (10)
Much needed. Ian Poulter arrests a terrible run of dropped shots with a birdie on the 10th.
His iron play, in to five feet, was sumptuous.
Bezuidenhout -1, Matsuyama -4 (5)
Talking about a player on song...
Hideki Matsuyama pipes another iron shot give himself a look at birdie, this time on the par-three fifth hole. Was that a four or five iron? Who cares? In rolls the putt.
Mickelson -7, Oosthuizen -4 (3)
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Mickelson -7, Oosthuizen -4 (3)
Louis Oosthuizen doesn't like that, wheeling his hand off his iron on contact, but it clings to the edge of the fourth green.
Phil Mickelson reaches for a six iron, sizes his approach up, and then steps back - I think's he asking for the drone above the green to be moved! "Can you radio in..." Lefty tells whoever needs to know.
The drone moves on, and Mickelson says thanks. But after that mini-drama, he overcooks it and finds the sand.
Casey -2 (6)
Back in the groove. That's tremendous from Paul Casey, who whips an iron into eight feet and then sinks his birdie putt.
Great golf.
DeChambeau -2 (9)
Bryson DeChambeau hits the turn one under for his round and two under for the tournament - five shots off Mickelson but I wouldn't get the panic button out just yet.
Plenty of golf left in this and DeChambeau is playing pretty solid - just needs to make a few more putts and he'll be right back in this.
Mickelson -7 (3)
Whether you like him or not, you can't deny Phil Mickelson is a real crowd puller - he's the man they all want to see at Kiawah Island today.
Especially the way he's started his round - Phil the thrill!
His birdie at the third hole was his 373rd career birdie in the PGA Championship since 1993, most of any player in that span.
Image source, Getty ImagesMickelson -7, Oosthuizen -4 (3)
He's got the shots and he's getting the breaks today too.
Phil Mickelson skirts the front bunker on the fourth fairway with his drive, taking a bounce off the bank and diverting beyond the second expanse of sand behind it. Prime position.