The 79th Masters Tournament was billed as a coronation, the much anticipated week when world number one Rory McIlroy, fresh off 2014 victories at the British Open and the PGA Championship, would complete the career Grand Slam at the tender age of 25, and cement his place in the golfing firmament.  In the event, The Masters did indeed write another chapter in the changing of the professional golfing guard, but it did so not by further stocking McIlroy’s jewel case but instead by ushering 21-year-old Jordan Spieth into the ranks of the game’s genuine elite – and, perhaps, providing McIlroy with some serious competition going forward.  Certainly Spieth arrived at Augusta rated among the favorites, for he had won a month earlier at Tampa’s Valspar Championship, then, following a week off, finished 2nd at the Texas Open and lost in a three-way playoff (to J.B. Holmes) at the Shell Houston Open.  Add in winter victories at the Australian Open (behind a stunning final-round 63) and the Hero World Challenge (by a record 10 shots) and he was, by any definition, on form.  But more significant, perhaps, was the nature of Spieth’s game.  Curiously, he is often characterized as “not a long hitter,” but he came into the Masters ranked a well-above-the-median 55th in PGA Tour driving distance  - which really might better be described as “long enough.”  And beyond this minor point, there was really little to question as his game is among the most balanced on the PGA Tour, and particularly excels inside 100 yards and upon the greens, where his putting stroke is the envy of most.  Indeed, time and time again over the weekend, Spieth holed mid-range putts of every conceivable angle on Augusta’s legendarily rolling putting surfaces; if there was a defining feature to this Masters, Spieth’s putter was it.  Thursday’s opening round began with high expectations for McIlroy and countless questions for world number 111 Tiger Woods, who was returning from a nine-week absence spent retooling his swing and his deathly ill short game.  But from the moment Spieth teed off at 1:15 p.m., this was to be his tournament, for he birdied eight of his first 14 holes and appeared on the verge of breaking the single round Major championship scoring record of 63 before bogeying the par-5 15th.  He would, however, birdie the tough 18th for a 64 – the Masters’ lowest opening round in 19 years.  More significantly, this gave Spieth a rare  three-shot first round lead in a Major championship, with his closest pursuers being 45-year-old Ernie Els, Charley Hoffman, and a pair of marquee players with plenty of Major bonafides, 2013 U.S. Open champion Justin Rose and three-time Major runner-up Jason Day.  On the downside, McIlroy could do no better than 71, defending champion Bubba Watson matched him, and Woods came home with a 73 which showed only limited improvement from tee to green but a marked improvement (meaning no disasters) within his short game.  And then there was 65-year-old Tom Watson, who slight-of-handed his way around in 71 over a golf course which, by his own declaration, has been too long for his game for the better part of a decade.  Particularly on so large a stage, Spieth would surely have been forgiven if he’d followed up his opener with a round in the low 70s, but instead he played flawless golf, posting three birdies on each nine while adding nary a bogey, and coming home in six-under-par 66.  The net result would be a five-shot lead over Charley Hoffman, matching the largest 36-hole margin in Masters history.  Further, Spieth’s two-day 130 aggregate was a new tournament record (bettering Raymond Floyd’s 1976 mark by one) and it also matched the lowest 36 hole score ever posted in Major championship play, a number posted by Nick Faldo (at the 1992 British Open), Brandt Snedeker (2012 British Open) and Martin Kaymer (2014 U.S. Open).  Hoffman, for his part, had posted strong rounds of 67-68, with the next nearest pursuers being Justin Rose (67-70), Dustin Johnson (70-67) and Paul Casey (69-68).  Johnson’s day, in particular, was worthy of note, for after double-bogeying the 1st hole, he proceeded to become the first man ever to record three eagles in a single Masters round (at the 2nd, 8th and 15th).  Woods also posted a solid round, but his three-under-par 69 still left him 12 shots behind Spieth.  Struggling on Friday were Watson (whose 81 prevented him from becoming the oldest man ever to make a Major cut), Sergio Garcia (68-74), Russell Henley (68-74) and Webb Simpson (69-75), as well as cutting-missers like Jim Furyk (147), Luke Donald (147), Martin Kaymer (151) and 55-year-old Fred Couples (153).  Avoiding the temptation to ride a string of pars in support of his big lead, Spieth made early Saturday birdies at the 2nd and 6th (which nicely offset bogeys at the 4th and 7th), then added five birdies from the 9th through the 16th to briefly forge his way to a seven-shot margin.  Most uncharacteristically, however, he then sloppily double-bogeyed the par-4 17th (sans penalty shots) to breath new life into an otherwise downtrodden field.  Justin Rose managed to birdie the 18th (his fifth birdie in six holes) to cut the margin to four, and it might have gotten even closer but for a superb Spieth up-and-down from right of the greenside bunker at the 18th.  His resulting three-day total of 200 bettered by one the tournament’ old 54-hole mark set by Woods (1997) and Raymond Floyd (1976), and staked Spieth to a four-stroke lead over Rose, and a five-shot margin over three-time Masters winner Phil Mickelson, who’d opened 70-68 before carding a third round 67 that might well have been lower but for bogeys at the 11th and the 17th.  Hoffman remained in the fight some six off the pace, while McIlroy (whose fine 68 might have really made noise had he not bogeyed the 16th and 18th) and Woods (whose own 68 generated some front nine electricity before fizzling out on the back) headed a group on six under par, eight off the pace.  The final round in many ways mirrored Saturday as Spieth responded to Rose’s opening birdie with a clutch three of his own before turning in 35, offsetting bogeys at the 5th and 7th with birdies at the 3rd and 8th to continue holding the field at bay.  If there was a decisive moment, it perhaps came at the difficult par-4 10th, where Spieth rolled in an uphill 20-footer for birdie to extend the lead to six.  A three-putt bogey at the dangerous par-3 12th represented a slight hiccup, and the lead was reduced to four when Mickelson holed a bunker shot for eagle at the 15th.  But Spieth still had the back nine’s two short, watery par 5s left to play, and when he methodically recorded the requisite birdies, it was all over.  Mickelson, for his part, fell into a share of second when Rose bogeyed the 72nd while McIlroy, paired with Woods and surely disappointed by his overall performance, made a late statement by carding a bogey-free 66 to play the last 45 holes in 15 under par, and climb into solo fourth.  Woods, on the other hand, could capture none of the magic of his Saturday front nine and, with only two fairways hit, did well to shoot 73, tumbling to a tie for 17th.  In the end, only a bogey at the last (off a missed five-footer) prevented Spieth from setting a new Masters scoring record (his 270 would only tie Woods) but among the records he did set were new 36- and 54-hole scoring marks, the lowest opening round by a winner and, quite significantly, the most birdies ever recorded for the championship (28).  He also became the second-youngest ever to don the Green Jacket, as well as the first wire-to-wire winner at Augusta since Raymond Floyd in 1976 - a span of nearly four decades.  "This was the ultimate goal in my golf life," Spieth stated afterwards.  But at age 21 and wearing his Green Jacket, it looked very much like he was only getting started.