Jordan Spieth dreams of second leg of astonishing Grand Slam

Having conquered the Masters in April, Spieth put himself in position to become just the sixth person to slip into a green jacket and hoist the US Open trophy in the same year after grabbing a share of the third round lead on Saturday.

It is an elite group that includes some of golf's greatest names -- Tiger Woods, Jack Nicklaus, Arnold Palmer, Ben Hogan and Craig Wood -- and a club Spieth admitted he has thought about joining.

"A little bit here and there, because I'd like to win two in a row," said Spieth after signing for a one-over-par 71 on Saturday.

"But tomorrow, once I get out on the golf course, I'll just be focused on the round and how to separate myself from the pack."

For only the second time in the 115-year history of the US Open, four men will start Sunday's final round tied for the lead and the 21-year-old Texan may well be the best prepared to handle the pressure of what is shaping up as an enthralling major showdown.

Australian Jason Day, South African Branden Grace and American Dustin Johnson will all be bidding for a first major title while Spieth can draw on the experience gained from having played in the last group at Augusta the previous two years.

"I think I'll be a little bit less anxious. I feel a little more relaxed right now after finishing the round versus when I finished Saturday at Augusta," said Spieth. "I was amped and already ready to start the next round.

"Right now I'll be a little bit more patient, I think, in not letting my mind wander and being focused on the next part of the routine to get ready for the round."

On his way to a green jacket, Spieth fought off challenges from some of golf's most intimidating figures. Woods, Phil Mickelson and world number one Rory McIlroy all took turns trying to rattle the young Texan, but Spieth held steady.

"If we can use that winning formula we had back in April, mentally, then all it comes down to is can I just pull off the shots and it's all on execution," said Spieth. "That's as hard of a golf course as you're going to see every year.

"So I'm going to need to execute a little bit better, because mentally I think I'll be strong enough to pull it off."

William Hill make Masters Champion Jordan Spieth, a 21-year-old with a remarkable sense of purpose, their 2/1 favourite, with Dustin Johnson offered at 11/4. Whilst Jason Day is 10/3 and Branden Grace 6/1.

South African Louis Oosthuizen is the best of the rest at 22/1, with Rory Mcllroy 125/1.

US Open: After Round 3 – 2/1 Jordan Spieth, 11/4 Dustin Johnson, 10/3 Jason Day, 6/1 Branden Grace, 22/1 Louis Oosthuizen, 33/1 J.B Holmes, 33/1 Shane Lowry, 66/1 Cameron Smith, 66/1 Patrick Reed, 80/1 Brandt Snedeker, 80/1 Henrik Stenson, 125/1 Kevin Kisner, 125/1 Rory Mcllroy

It stands at a lofty 300/1. No man has ever achieved the Slam in a calendar year. Tiger Woods held all four over two years. Expect Spieth's odds to tumble significantly if he ends up holding the US Open at Chambers Bay. St Andrews should suit his game perfectly which would leave Whistling Straits and the US PGA Championship in August. No point in getting ahead of ourselves. First up is escaping from Chambers Bay with the title. Which sounds a lot easier than it is going to be to achieve on such an exacting and mentally draining course.