Jason Day's birdie put skims a good four feet past. It is like sheet ice along that line.

Johnson tells Day to tap it in, which he does for a level par finish.

Now Dustin, how's the nerves?

Luke Donald: "If this goes to a playoff, not sure the greens can take another 18 holes! maybe they should just play it at another course."

Image source, Getty Images

This putt is over a very slick stretch of green.

It is closer to the hole than Spieth had, but perhaps more tricky.

Dustin Johnson will have plenty of time to mull it over as well as Jason Day plonks his bunker shot out and further away than Johnson's ball.

Iain Carter
BBC golf correspondent on Radio 5 live sports extra

"Last time an eagle won a major?...... Women's British Open Mo Martin 2014"

I can't take much more of this.

Dustin Johnson steps up with his five iron and catches it sweet as a nut, running the ball up the back stop and back down and to within ten feet.

He will have this putt to win the US Open. Can he succeed where Spieth failed>

Graeme McDowell: "That tee shot from DJ was outrageous....... What a finish.

Sergio Garcia: ‏"Back to my point, this is such a great championship @usopengolf that's why it deserves the best quality!!

Ohh!

Spieth gives it every chance, but his putt sits just short and wide.

He taps in for his birdie, taking Louis Oosthuizen out of the equation.

An eagle for Dustin Johnson - on the back of a great tee shot - would snatch the title from his hands.

Image source, Getty Images

Branden Grace has a poke up the hill from 20 feet for birdie. He is a couple of inches right and a couple of feet past.

A perfect guider for Jordan Spieth though.

The American steps up to take a look at an eagle putt that could land him his second Major of the year. Fifteen feet to the hole. To glory.

Here we go...

Luke Donald ‏on Twitter: "What a couple of shots by Spieth on 18!!"

South African cricketer AB de Villiers: "No matter who wins, this was well worth the effort of staying up all night! Incredible action #USOpen2015 @usopengolf"

Image source, Getty Images

The challenges are coming in from all angles.

Dustin Johnson - who seemed dead and buried - keeps up some pressure behind Jordan Spieth, holing his birdie putt on 17 to move to four under.

He is still in this, striding to the 18th tee on exactly the score Spieth did.

And he has hit a howitzer right down the middle of the last.

You just can't call this. What drama.

Is that the shot that finally puts this to bed? Jordan Spieth nails his 280-yard second on the 18th, riding the ramp at the back of the green and finishing up within 15 feet.

He will have a putt for an eagle and six under. Two putts for five under and a birdie. Not worth thinking about anything else surely?

Graeme McDowell: This is crazy stuff..... Jordan makes birdie to win?

Sergio Garcia: This is getting crazy!! 4 guys still in it after @JordanSpieth double on 17! Nail bitter!

Image source, Reuters

Jordan Spieth, what have you got for us?

The American is under so much pressure, they will need to treat him for the bends after this.

He steps up to the 18th tee, chats over his tee shot and wallops one.

Where has that gone? "Be soft," Spieth pleads as the ball bounces. He needn't have worried that is just dandy.

He needs a birdie to finish this tonight. And that is a good first step towards it.

John Patrick on Twitter: "#bbcgolf who said this was all over ??? #commentatorscurse"

Would you believe it!?

Jordan Spieth's tiddly little putt to make a bogey refuses to drop. It never even looked likely either, sliding past from three feet.

Groans all around the gallery, followed by encouraging roars. Spieth marches off to the last amid a maelstrom.

Have his senses and skills been scrambled or can he collect himself to pull through?

Image source, Getty Images

Meanwhile over on the 18th, ice-cool Louis Oosthuizen has knocked in his birdie putt to rack up his sixth birdie in seven holes.

He finishes his day on four under and sits back to wait and see.

Jordan Spieth misses with his par putt on 16, not enough legs and he has one of those twitchy little three-footer for a bogey. Five under at best for the American.

Sergio Garcia on Twitter: "What a putt from Jordan Spieth on 16! Wow"

Former England batsmen Kevin Pietersen on Twitter: "Helluva putt...game over! #Spieth"

Image source, Reuters

Now then. Is there another twist in the tale?

Jordan Spieth apparently had the tournament signed, sealed and delivered on the 16th green.

He contrives to reopen the betting with a dog of a tee shot on the par-three 17th, spraying short, left and into the tangled stuff.

He punches out with a decent-enough recovery shot, but this is a roller-coaster 20-footer just to make par.

Louis Oosthuizen's run of birdies has come to an end with a par on 17.

The South African has also found sand on the par-five 18. He remains on three under.