Rafael Nadal just defeated Roger Federer in the longest championship match in Wimbledon history, and it had the feel of a torch being passed.

From the former tennis king to the new one.

Nadal has been whittling away at Federer’s supremacy, beating him now and then … to beating him regularly on clay … and now he has gone into Federer’s house — the All-England Club — and defeated him on his favorite surface, grass.

At Centre Court, where Federer had won the previous five championships.

Odd thing about tennis: It reminds me quite a bit of boxing, at times like these.

On the surface, the sports have little in common, aside from the mano-a-mano aspect of it. One is graceful, polite and pastoral. The other is brutal, rude and primitive.

But the commonalities are there, particularly when it comes to “champions.”

The great champion — and Federer certainly wass one — carries with him the heartfelt conviction that he will never lose. He hasn’t before. Why should he now?

At critical points, that reflexive certainty comes to the fore, and the champion delivers. With one more passing shot or one more shot to the head.

Both tennis and boxing seem to me very much mental games. When you believe, when you know, you are nearly impossible to defeat. But when that defeat finally comes … often that realization diminishes the former champion significantly.

I could list a dozen great boxing champions who were never the same after that first defeat was pinned on them. Three that spring to mind are Mike Tyson, Thomas Hearns and Roberto Duran.

In boxing, the beat-down that the ex-champ often takes contributes to the mental baggage he forever after lugs around.

In tennis, the physical punishment is far less, but the memory remains. “When I had to come through … for the first time, I didn’t.”

Some of those who are particularly strong-willed can come back and do more winning. Even of significant events. But it’s never the same. The aura is gone. It emboldens your opponents. More significantly, it weakens your own resolve.

In the Wimbledon final today, which had to be special to prompt me to watch the final hour … Nadal refused to crumble before the Federer reputation, and as tight as the scores were, Federer had almost no real chances to get close to winning — let alone play for a match point. It was Nadal who came close so often to scoring the decisive point.

When it was over (as so often happens in these cases) onlookers are left wondering what took so long. Why didn’t the younger, stronger, quicker guy win even sooner?

Nadal has shaky knees, at age 22. Tendinitis, apparently. And that could keep him from going on a surge of dominance to rival that of Federer’s half-decade. Federer is 26 (27 next month), and that is on the edge of old-age, in modern tennis.

In fact, there were times today when he looked decidedly old. A bit weary. A guy who allowed outside events to distract him — as on the second-to-last point of the game, when he seemed to ask the chair refereee to intervene in some issue in the stands. The sort of aside the laser-focused Federer probably would have ignored, two years ago. The sort Nadal didn’t seem to notice, today.

But that is a function of age, and time at the top.  You start to lose that one-track mind. You don’t go soft as much as realize there are other things in the world.

The final score was 6-4, 6-4, 6-7, 6-7, 9-7. And it had the feel of a succession being acknowledged.

Rafael Nadal never again will be an underdog to Roger Federer. The aura of invincibility is gone, and the reality of Nadal’s clear superiority has been established. Both players know it. All of tennis knows it.