It’s a sensation unlike any other. Primordial in the way it overcomes and envelopes you; individual in its invocation of emotion, yet communal in its context. It’s physical in the way it stirs you, yet mental in the way it makes your mind race through memory and anecdote. It’s not fear, nor excitement; it’s not quite anxiety, nor happiness. It is truly unique. It’s a sort of recognition; a recognition of greatness. The sensation and anticipation that you are about to witness something great in front of your very eyes.

The opening lick of James Hetfield’s guitar. The quiet tapping of Lars Ulrich on the high-hat. Fifty-five thousand people rise to their feet as a steady roar fills the stadium. The rhythm builds as Kirk Hammett’s electric lead comes in.

Exit light; enter night.

Enter Sandman. Enter the greatest. The greatest who has ever lived.

Mariano Rivera’s entrance music inspires such emotion that whenever Yankee fans hear the 1991 Metallica breakout single, it’s likely their minds can’t help but race back to the memory of when the first saw, and heard, the single greatest relief pitcher of all time trot into the infield of The House That Ruth Built and record one of his 563 combined regular season and postseason saves.

As the 2009 World Series comes to a close, the rest of the baseball universe, outside of its capital in the Bronx, has once again had the opportunity to be October witnesses to the greatness that is Mariano Rivera. For a man who needs no introduction, save the holy riffs of Metallica, behold a brief look at his resume of dominance:

His career 2.25 ERA is by far the lowest of any reliever ever. He is riding a current streak of 13 consecutive seasons with 25 saves; in nine of those he posted an ERA south of 2; in five of those, a WHIP under 1. His 526 regular season saves are second to only Trevor Hoffman, who is three years older and has a career ERA half a run higher. Since his first full season in 1996, Mo has never averaged more than three walks or one homerun surrendered per nine innings. Left-handed hitters- lefties- have a career average of .206 against the right-handed Rivera. He has gone to a three-ball count to 14% of the hitters he’s faced.

Often it is argued that relief pitchers such as Dennis Eckersley and Goose Gossage were better, more dominating, pure pitchers. Mo has averaged 80 innings pitched per each 162 game season, while Eckersley and Gossage averaged 156 and 118, respectively. In 1992, Eckersley picked-up both the AL Cy Young and MVP- two honors that have alluded Mariano. In 1981, Gossage posted a miniscule ERA of 0.77; Rivera has never had a season with a mark even within half a run of that.

However, as the Fall Classic has yet again attested to, what truly defines Mariano is his postseason play.

Rivera’s play in October makes him not only, indisputably, the greatest relief pitcher of all time, but perhaps the most consistent and flawless athlete performing in the playoffs in any major sport, ever.

I welcome the retort of both my fellow columnists and the Sun readership alike to present a case that any other athlete has been as close to perfect in their individual role on their given team in postseason play. I believe only Tiger Woods may have a legitimate claim to such a designation.

He holds the postseason records for most saves, lowest ERA, consecutive save opportunities converted, two-inning saves, appearances, and consecutive postseasons with an appearance.

Not to mention his four championship rings in five years in the ‘90s, none of which it would seem likely the Bronx Bombers would have won without Mariano’s dominance out of the bullpen.

The argument can certainly be made, and in fact has been, that other elite relief pitchers in recent history have had the pure skill and ability to achieve such postseason merits if their teams were the same caliber of the Yankee teams over the past 15 years.

Such hypothetical claims might be true, but that doesn’t change the fact that Mariano really has been that dominant in the postseason, and that that reputation has a real, salient, influence on reality when Rivera takes the mound with a lead in the 9th inning.

In a story Tom Verducci wrote for the October 5th issue of Sports Illustrated on Mariano Rivera, entitled “Mariano Saves”, the ‘Ducc interviewed a number of American League hitters on their experiences facing Mariano Rivera and his deadly cutter.

“I’ve actually had a couple of guys tell me the approach to take against Mariano is not to swing at all,” said Tampa Bay outfielder Gabe Gross in the article.

Against a pitcher who has a career average of 2 walks per nine innings, professional hitters actually believe they are best suited to just stand in the box and not even take the bat off their shoulder when facing the single most dominating pitch ever thrown (the only contender perhaps being Nolan Ryan’s fastball).

Reflecting on his teammate, Yankees pitcher Chad Gaudin told Verducci, “Nothing derails [Mariano]. No emotions get in the way. Ever. He is able to take all that energy of the moment and channel it into everything he has to do. Why doesn’t everybody do that? Not everybody has the power or self-discipline.”

That’s why, in the ninth inning of a piercingly-cold late October (or early November) night in the Bronx, with the Metallica riffs pumping through the most storied cathedral in the history of professional sports, Mariano reigns supreme. Chills run-up your spine and the hair stands-up on the back of your neck. The sensation for a Yankee fan in the stands is truly unique. But for the opposing hitter, make no mistake; the only emotion he feels is fear.

“You know what’s coming,” said former Kansas City Royal Mike Sweeney in the SI article. “But you know what’s coming in horror movies too. It still gets you.”

Say your prayers, because Mariano doesn’t save; he destroys.

Welcome home, Number 27. The Sandman has been waiting for you.