AUGUSTA, Ga. — Every day after he finished his round in the Shell Houston Open two weeks ago, Jordan Spieth’s younger sister Ellie, a special-needs teenager, asked him if he won as he came off the course.

“Not yet,” Jordan would tell her. “Not yet.”

Then, finally, “no.” He finished second.

Now, dear Ellie, there’s no more waiting.

Your big brother Jordan just won the biggest golf tournament in the world.

The green jacket that 2014 Masters champion Bubba Watson slipped on Spieth’s shoulder’s in the Butler Cabin didn’t quite seem to fit. For those who don’t know, that ceremonial jacket is basically a rental until the new champion is fitted for a permanent version.

But the moment, and four days of unrelenting major championship pressure, enough to make a lad of 21 like Jordan crack like an almond, that wasn’t too big for him in the slightest.

He not only won, he won emphatically, by four strokes over Phil Mickelson and Justin Rose and by six over world No. 1 Rory McIlroy.

Major champions all, they lined up and took their shots at Spieth like battleships executing a naval bombardment.

Spieth never flinched.

Oh, he made a bogey here and there and one sloppy double on No. 17 on Saturday to briefly give his pursuers hope.

But he opened Sunday birdie-par-birdie, statement-making golf, communicating to the rest of the field via the big scoreboards that stand like sentinels across Augusta National’s manicured landscape that he wasn’t going to come unglued by something as mundane as Sunday at the Masters.

He had an answer for every misstep. Spieth made four bogeys Sunday. He counterbalanced them all with birdies except for the last.

On 18, he missed the putt that would have given him the Masters’ outright scoring record at 19-under-par 269. Instead, he came home in 270 and will have to share the record with Tiger Woods.

Poor lad.

During last year’s Masters, when Spieth tied for second behind Watson, Colin Montgomerie said he thought the then-20-year-old Spieth had an old head on young shoulders.

On Sunday, that seemed to be true in every sense. Instead of being worried about the champions trying to chase him down — or, like most 21-year-olds, about finding a job when they graduate from college — Spieth pulled off his Under Armour cap and reorganized his diminishing ’do.

“His biggest concern at 21 is he’s losing some hair,” Sir Nick Faldo, still fully coiffed at 57, said on CBS as Spieth marched up 18.

For sure, this Spieth kid has first-world problems.

Here’s two more: what to serve at next year’s Champions Dinner, and will he get carded if he orders a glass of wine from Augusta National’s vaunted wine cellar?

Being that he’s the first Texan to win the Masters since Ben Crenshaw 20 years ago, we think we have a good handle on the main course:

“Jose Maria, Vijay, how do you like your barbecue, pardner?”

A media center full of golf writers and commentators were hard at work here Sunday night, markers and rulers drawing parallel lines to Tiger Woods’ breakout victory as a 21-year-old. (Woods by about six months is still the youngest Masters winner.)

It wasn’t as masterful as Tiger’s 12-stroke romp in 1997. Spieth isn’t the kind of player who’s able to dominate the course with his length.

He’s more tactical, surgical, winning with focus and precision. He seemed to hit all the right shots and make all the key putts at all the right times and, when he missed, he seemed to do so in all the right places.

Consider the par-4 11th, this year’s hardest hole. Spieth pushed his drive right into the pines but punched out low and right of the green where Larry Mize chipped in to electrocute Greg Norman in 1987. He chipped straight up the slope to about 4 feet and coolly made his par.

As if on a tour of great Masters recovery shots, on No. 16 Spieth hit over the green where Woods chipped in back in 2005. Rose had a putt for birdie but missed, while Spieth got up and down for par. A two-stroke swing avoided, the tournament was essentially over.

There were comparisons to Crenshaw, a 1970s Texas phenom, but perhaps the comparisons should be to another Texan: Ben Hogan.

Spieth won, with his mind, a tournament he only once dreamed of winning.

He said Ellie will be wanting him to bring her home a prize.

How about his green jacket?

Follow Scott Rabalais on Twitter: @RabalaisAdv.