The weather has perked up this afternoon, enough so for Jon Rahm to begin his round in just a polo shirt... it seems a long time since Jordan Spieth headed out in a gillet.

Talking about keeping your cool...

Jason Day gets the wobbles on six and seven, making bogey on both to move back to one over. After his bogey on one, Sergio Garcia has got things together and he makes an excellent par save on seven before lampooning a drive up eight. Zach Johnson is in this group too. I felt this course may suit his style but not so far, two over.

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Lee Westwood may be dubbed a 'nearly man' but you have to salute his career. A full 23 European Tour wins, a couple of successes on the PGA Tour, a former world number one, he's packed a lot in.

His record of 77 starts in a major without a win is bettered by only Jay Haas on 87.

Lee Westwood gets a good reception as he makes his way to the first tee. Was that a doff of the cap or a quick ruffle of his hair? Either way, the Englishman is about to get his Open under way...

He'll be playing alongside Spaniard Jon Rahm and American Patrick Reed.

Brooks Koepka claimed a share of the lead when he knocked in from the bunker on the 17th, now he is in almost identical situation on the last.

He can't. Can he? Almost. Another clean swish of the sand wedge, sees the ball trundling towards the trapdoor, but it doesn't get enough swing in the end.

Never mind, it is an easy tap-in. A fantastic 65 for the American, who is aiming to become only the seventh man to do the US/British Open double.

There's something about Royal Birkdale which American and Australian players love, so perhaps seeing two from the US at the top isn't a surprise.

In nine runnings here, only once has a player from outside of those nations claimed the title - Padraig Harrington in 2008. He's among six Americans and three from down under.

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Home favourite Tommy Fleetwood hasn't started the way the Southport crowd would have been hoping, but he still gets a healthy applause on his way down to the 18th green.

Can he finish on a birdie? No, that's not dropping.

The long-haired Englishman cards six over for the day after a rough front nine was followed by bogeys at the 16th and 17th, and has one heck of a challenge on his hands if he's to make it a long weekend at Birkdale.

Rory McIlroy on the tee then, joyous sound from that one iron. Sweet as a nut but a touch left and in the rough, though the ball is visible.

"On the tee from the USA... Dustin Johnson".

DJ rolls the sleeves up his jumper slightly, he's dressed head to toe in a light colour, unshaven face. He's on the other side of the fairway to Rors and also in the rough.

Schwartzel, a Masters winner of course, also goes with iron. A few grumbles from the fans and he's next to McIlroy.

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Now, what a group we have on one... Rory, DJ and Charl Schwartzel.

Watch the moment Andrew 'Beef' Johnston holes out from off the green at the 6th.

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Adam Scott has a dashing cream jumper on today. It's just like what a dad wears on Christmas Day. Rolls in a birdie on five to move under par.

Brooks Koepka splits the fairway with his drive, he takes a big divot out with that approach to the green and it skews his ball bunker-wards, trickling away from the good stuff.

That's not troubled the American too much so far...

The par-five 17th has coughed up six eagles today... make that seven. Brooks Koepka, like Wales' Stuart Manley earlier, splashes sand all over bunker-cam and splatters the hole with a ball.

The US Open champion deliciously clips in for a three, and a slice of Spieth's pie.

Spieth is two shots clear of Ian Poulter, who is safely back in the clubhouse with his card signed and sealed, plus American pals Brooks Koepka and Justin Thomas.

Most of the chat around Thomas has centred on his clothing choice (he looks like he is going to a job interview for a start-up media agency with a tie and cardy combo).

The American's golf has been pretty sharp too. He has just eagled the 17th to move alongside Poulter and Koepka.

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Jordan Spieth struggled to hit the fairway during his first round, but that didn't prove too much of a problem for the American.

Spieth still made 78% of greens in regulation and did not drop a shot on day one at Birkdale.

Jay Townsend
BBC Radio 5 live golf expert at Royal Birkdale

The first putt we've seen him miss that we'd expect him to make. A disappointing end to a great round. I will go out on a limb, he will be Open champion, I'm just not sure which year.

He is so well grounded, he's already thinking about tomorrow. He is so strong minded. Not the best player out here but he has that intangible thing, that something between the ears.

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Talk about commentator's curse. The bloke on the telly says there is "zero chance" that Jordan Spieth won't hear the sound of ball hitting cup with a seven-foot birdie putt on the last.

Guess what? Yep, he missed it. Never mind, Spieth taps in for the par and for a two-shot clubhouse lead.

Well played young man. The two-time major winner looks to be the man to beat.

Steady start from South Korea's Kim Si-woo. The 21-year-old, who became the youngest winner of the Players Championship in May, has carded a level-par 70 on his Open debut.

Jordan Spieth dug himself out of a hole on the 16th, but he didn't leave a spade on the side of the green for co-leader Brooks Koepka.

Koepka drops his first shot of the day on the same par four, allowing Spieth to move two shots clear.