The trainer thought beforehand the reaction that occurred after Errol Spence did a smash-and-grab on Chris Algieri Saturday night in Brooklyn would happen.

“I thought going in, this is where America falls in love with Spence,” said Derrick James a couple days after the kid’s decapatative hook scrambled the Long Islander’s senses, forced a stop at Barclays Center and snagged massive attention from a star-starved boxing fandom.

“I heard people say before that Algieri would win. But Errol is what America is … we are the best, we want to continue to be the best. And calling out the best is the basis of America. He wants to be THE MAN.”

You get the sense James, like Spence a Texan, is still a mild bit salty at the lead-up to the fight. Algieri said he was going to “expose” Spence … but what was exposed, James said, is the true potential of his guy.

Speaking of true potential … and circling back to “calling out the best” …

The best boxer on the planet is as of now retired. Floyd Mayweather could still beat any and all at 147 without a single day of training camp, it could be argued. But the 26-year-old Spence leap-frogged some other candidates for “maybe” foes if and when Mayweather un-retires. I asked James, could we, would we see Mayweather vs. Spence? The wizened lion versus the guy who some see as an heir to “Money”?

“It will never happen,” James told me. “It doesn’t make sense. Floyd is retired.” Also, the 20-0 Spence has opened eyes, but still has work to do. Like grabbing titles and taking down folks higher on the ladder at 147.

But … but … didn’t I hear that Spence knocked down Floyd when they sparred before Money fought lefty Robert Guerrero? “He never knocked Floyd down,” the trainer, at 44 now firmly ensconced in that cluster of tutors who seek to continue their way into that den of exalted vets, with the Freddie Roaches and such. “They had great sparring. And Floyd has NOTHING to prove.”

We talked more about the win over Algieri and how James was happy the New Yorker tried to work inside. I was curious, does this win mean Spence is right now to be considered BETTER than Amir Khan, who was neck-and-neck with Algieri when they battled last year. Nossir, said James, basically offering a version of the “styles make fights” explanation. His answer, though, had more to do with the strength of Spence. He’s a TRUE 147, not like so many of the crew clustered at the upper tier here. Khan was coming up, Algieri was coming up. Garcia just came up, etc. Spence fought at 152 at the 2012 Olympics and belongs here, now.

James didn’t give his guy an A-plus. Maybe if Algieri had been better, he told me … How so? Because, James stated, Spence could have been more defensively aware. He walked through Algieri’s shots without proper respect. “He steamrolled him.” Message: Not all foes will be able to be steamrolled.

And with that sort of showing comes chops busting. Boo birds, the Twitterati speaking with the bravery that comes from being out of range and the clarity that comes from never having tried to climb a hill, let alone a mountain, they spoke up. I was poked by a Tweeter who asked me to look at Spence’s breasts. Gynecomastia, the amateur physician told me, could indicate PED usage. A world class boxer even Tweeted out a Spence boobs crack the other day …

“I saw that,” James told me. “Spence won’t even take vitamins! USADA has been coming to his house for years. He was No. 1 as an amateur for four years. He couldn’t go anywhere without telling them where he was going. I promise you, he doesn’t do any of that stuff! I know, I do his strength and conditioning.”