Kevin Garnett was talking about defending the pick and roll Monday, which is the most essential play in basketball and one that has been giving the Celtics all kinds of trouble ever since Steve Nash and the Phoenix Suns worked it to death a little over a week ago.

In his career Garnett must have seen the pick and roll, what? Fifty thousand times? More?

Listening to him talk was like listening to John Hannah talk about leverage or Pedro Martinez talk about working both sides of the plate. The mundane can truly be fascinating with the right person speaking.

“The biggest thing is the angle which you show to make the small, which is the guy with the ball a lot of times, bow out,” Garnett said mimicking the action of pulling on the strings of a bow before loading an arrow. “Bowing out is making a guy go out away from the basket. A great show is when you make the guy go away from the basket and the small goes under you and get right back in front.

“When you’re dealing with a shooter, Dirk [Nowitzki], Chris Bosh or Rashard Lewis, you have to mix it up and get into my tricks and schemes. It’s about timing and effort and how much of a show versus, [for example] Mo Williams and LeBron James. That’s tougher because Mo can come off and score the basketball, but you also have a shooter in LeBron. It all depends on who’s in the pick and roll.”

Garnett possesses one of the sharpest defensive minds in basketball, but he rarely goes inside the game like that. Fortunately he was in a mood to expound. 

“The pick and roll is the pick and roll,” Garnett said. “It’s been 15 years for me and I haven’t seen it change. It’s about who’s in the pick and roll. [John] Stockton and [Karl] Malone. Malone’s a great sealer, meaning that he can put you behind him so you can’t get back in front of him. John Stockton was very good at cutting the angle, like when Joe Dumars and Grant Hill were together. He takes the space off the angle of the screen. Those are guys who really know how to play pick and roll.

“Chris Paul has a little bit in his game. Chauncey Billups has the same thing. Pick and roll is about who’s in it and how hard of a show or whatever the scheme is and how hard you’re doing it. It’s going to be like that until the end of time. As long as they’re playing basketball the pick and roll is going to be involved. It’s probably the hardest, besides the individual, thing to guard. We have schemes for that.”

Fifteen years in the league and Garnett still lives for the challenge of shutting down great players like Lewis or Nowitzki.

So why are guys with names like Oleksiy Pecherov and Dahntay Jones having career nights against the Celtics?

It can’t be the scheme because the scheme works. It’s won a championship and led to some of the most impressive defensive metrics of the modern era when everyone’s healthy.

So if it’s not the scheme, it must be the players. But since we know the Celtics possess a number of good, if not great, defensive players then it has to be something else.

A lack of focus? Tired legs?

How about a lack of respect for who they’re playing?

“I don’t think it’s slippage,” Ray Allen said. “We still have to respect other teams that are coming at us. The other night Dahntay Jones scored 25 points. He’s a guy we had in camp two years ago. We didn’t adjust to his ability to score that night. Whatever we were thinking – he couldn’t make shots or they wouldn’t give him the ball – they did. We didn’t recognize that quick enough to try to take that away.

“We have to respect every team. That’s the thing we did in [2007-08]. Every team we played we respected. We knew there were teams we were supposed to beat and that ultimately gave us home-court advantage.”

It’s not as if Dahntay Jones will ever be mistaken for LeBron James, and therein lies the problem. The Celtics have shown at times this season a kind of careless disregard for teams and players they don’t respect. It cost them against Indiana and it almost cost them against New Jersey and Minnesota.

It’s also worth pointing out that three of Boston’s worst games (Minnesota, New Jersey and Indiana) came on the road on the back end of back-to-back games, which speaks to fatigue.

So while the Celtics pick-and-roll defense has been sloppy, and there is some fear that their veteran legs are already wearing down, what’s most disconcerting about the Celtics’ recent play is that most of it is self-inflicted.

“Through training camp and the first five games we got off to a great defensive start,” Doc Rivers said. “And then I think we thought it was going to be easy from that point on, and it hasn’t been.” 

This is part of the deal with the Celtics. They are confident to the point of arrogant and their cockiness is no real secret throughout the league.

“Prideful,” Garnett called them. That works too, and it’s a double-edged sword because their confidence has saved them on a couple of occasions as well.

When the Hawks and then the Cavs were pushing them to unlikely seven-game series during the championship run, to a man the Celtics all believed they were going to win. Especially when everyone else thought they were in over their head.

Right now all of this is part of “the process,” as they like to call it. The process is playing 48 minutes a night for 82 games in places like East Rutherford, N.J., from here until April. The process is travel and hotels and practice and convincing yourself that on any given night Dahntay Jones can go off for 25 points if you’re not careful.

When the players were young and trying to prove themselves, the process was enough of a challenge, but at some point it becomes a struggle for veteran players to fight through it.

“That’s all we talk about is the opponent being us, and the process,” Rivers said. “And the process is boring, but you can’t allow it to get boring. It’s monotonous. You do the same things every day. You work on the same things every day and you can’t be satisfied with good. You have to be better than good and that’s where we’re at.”

In the grand scheme of things the Celtics will probably be fine. Two straight losses and a handful of clunkers in November won’t define their season.

But many teams have tried before to turn it on and turn it off whenever they choose. Very few have been able to figure it out in time.

“That’s going to be a challenge for us,” Rivers said. “We get good, we win a couple of games, and we tend so far not to have that 48-minute capacity yet. That’s not anything that’s alarming [right now] but to be great at the end, we have to be a 48-minute team. Right now, we’re just not. We go in and out even in the games we’ve played well.”