If he had not already, Madison Bumgarner solidified himself as an all-time great with last night’s masterpiece in Flushing.

Greatness: the only word that can be used to describe Madison Bumgarner. Rather, the only word that can be used to explain what transpired at Citi Field last night.

To any individual who doubted the legitimacy of the 27-year-old’s playoff dominance, the baseball world sincerely hopes that you sat your behind on your living room couch and watched the bottom half of each inning unfold. If the man had anything else to prove, which he did not, he laid it all on the line last night, and came out smelling like roses.

Make it three do-or-die games. Make it 23 innings of shutout baseball.

From the 2014 NL Wild Card game — another complete-game shutout, to five brilliant innings of one-run preservation in Game 7 of that same year’s Fall Classic, Bumgarner, a three-time world champion, did not need to earn his stripes.

But that is what distinguishes one-hit wonders from long-tenured greats; nice stories from baseball legends.

When push comes to shove, the southpaw always makes it count, and he put that sheer grit on full display last night.

With another flash of immortality on one of the most substantial stages in sports, MadBum, as they like to call him, improved his career postseason record to 8-3 over 15 appearances (13 starts), watching his ERA dwindle to 1.94 in the process.

Coming off his most previous postseason endeavor, which was arguably the greatest overall playoff pitching performance in history, and undoubtedly the greatest World Series pitching performance in history, he had an extremely tough act to follow up in front of 45,000 hungry fans who, for the most part, took the “show me” attitude.

Well, that is the unfortunate approach most MLB fans were taking, including myself. Heading into this season, with all of the even-year speculation with the Giants, a friend came to me and asked point blank, “If Madison Bumgarner retired today, would he be a Hall of Famer?”

I directly responded, “He needs three more quality years. Give me three more quality years and I’d say yes.”

At the time, that was probably an accurate measurement. Now, it is not even close to a fair assessment.

If the 2007 first-round pick decided it was time to hang up the cleats, he would go down as a baseball immortal. Would he go down as one of the best to ever pitch (which he has the capability of becoming)? No, probably not.

Immortal? Yes. Legend? Absolutely. Icon? You get the point.

When it comes to the makeup of a champion, a few factors come to mind. First and foremost, though, an ability to weather the storm takes forefront. When your team needs you the most in a nearly impossible environment, can you bend but not break?

The chief real life example of that circumstance is a playoff game on the road, a department in which MadBum absolutely obliterates his closest competitors.

Let’s just go with fact (Best Road Postseason ERA, min. 25 IP):

Decent company, huh? He does not merely contest them, he dominates three of the most superb arms in the history of the game.

When judging Hall of Fame candidacy, it is not all about longevity, compiled numbers, or packing a stat sheet. In certain cases, often the most intriguing ones, it comes down to pure value and impact. Essentially, a question as to what that person truly meant to his team.

That question will never come about in a negative sense with Madison Bumgarner, and he made sure of it last night. Right when the Mets tried to claw their way back to life, he readjusted. When he worked his way into any trouble, he acted as if the game was being played on April 12.

When he completed a four-hit shutout, fortifying himself with the best to ever put on major league baseball uniforms, he acted as if that was the expectation — and it was.

That is the sign of greatness.

I have since come back to that thought-provoking offseason question. Yes, he would be inducted, and in a swift and undeniable fashion.