It’s early in the first quarter, but the Nets have already tipped their hand. They’re going to be playing off the point guard and looking to help on the Celtics stars. Gabe Pruitt, in his second year out of USC and getting his first extended run with the top unit, recognizes the defense and knocks down a 3-pointer. Over on the Celtics bench, Doc Rivers allows himself a little smile.

The Nets aren’t changing. Not yet anyway. Pruitt recognizes it again a few minutes later and the play ends with the same satisfying result, 3-pointer, and now New Jersey has to mix it up. Pruitt sees the defender close in, he loses his man in traffic and hits Kevin Garnett for a dunk.

Pruitt emerged from his 44-minute performance against New Jersey on Sunday night with a few bumps and bruises—“You did today what (Allen) Iverson has done for 10 years,” Doc said—and a line that read: 11 points, 12 rebounds and seven assists. He also earned some respect from his teammates and coaches.

“He really played under control,” Paul Pierce said after the game. “He understood what we needed.”

Pruitt played, essentially, the way Rivers wants his point guards to play. Like a lot of ex-players who went into coaching Rivers is demanding of his point guards. He was a good one himself, a battler who emerged from the second round of the draft to take command of a high-powered offensive team in Atlanta with Dominique Wilkins, and then, later, a consummate pro with the Knicks, Clippers and Spurs.

But Rivers rarely, if ever, talks about certain sets or specific plays. When he talks offense, he talks about flow and ball-movement. These are abstractions. You’ve heard the analogy that professional basketball is like jazz: Rivers needs a bandleader--someone who makes sure that the virtuosos have the space to flourish and is also able to keep the time.

The Celtics are a defensive team, that’s where their energies lie. They use their defense to generate offense, and when they play in the half-court they rely on crisp passing rather than isolations. It’s a beautiful way to play the game of basketball, unless there is no flow. Then it’s just unscripted noise.

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It didn’t take long to see what the Cleveland Cavaliers were going to throw at the Celtics in the playoffs last year. They were going to take whoever was guarding Rajon Rondo and have them help on everyone else. If Rondo wanted to shoot jump shots, that was fine with Cleveland.

Rondo is an immensely talented package. He is a fantastic rebounder and a first-team All Defense player in the making. He has the ability to get past everyone in the league and, once he gets there, he can make good decisions and finish in the lane. But he’s not Dale Ellis. He’s not, in other words, a standstill knockdown jump shooter.

This took the Celtics out of their rhythm, and because Cleveland is beyond conservative offensively, there were very few fastbreak options available. The Celtics were left to play 1990’s bump-and-grind basketball, and it was ugly.

Cleveland was uniquely capable of playing that kind of defense because the Cavs have solid on-the-ball defenders at almost every position, and because they have LeBron James. The attitude being: We’re going to slow it down so that it’s close at the end and then we have LeBron and you don’t.

The Celtics stayed alive primarily because Pierce out LeBroned LeBron in Games 5 and 7. (The other key moment in the series came in Game 1 when Cavs coach Mike Brown outsmarted himself by putting Joe Smith in for offense, which also meant that Smith had to cover Garnett. KG made him pay with a slick move on the low block for the decisive basket.)

It bodes well for his future that Rondo is good enough to cover up for his lack of a reliable jump shot, but you can be assured he will see the strategy again and again this year.

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Eddie House is not a point guard. Not really, anyway. He is, in fact, a great jump-shooter and it’s a skill that has kept him employed in the NBA long after several of the point guards who were drafted of him in 2000 (Mateen Cleaves, Erick Barkley, A.J. Guyton, Khalid El-Amin) came and went.

But House is a good backup point guard for the Celtics because he understands flow. He knows how to keep the ball moving. That he might go off for three or four 3-pointers is a highly-desirable bonus. In the opening minutes of the fourth quarter against New Jersey, House was paired with Pruitt in the backcourt and he did just that, knocking down three straight 3’s to put the Celtics up by 20 points.

That’s why Pruitt’s emergence Sunday night was so important. If he can play at this level during the season he allows Rivers to pair him and House together in the backcourt in spots, and make up deficits or lengthen leads, quickly.

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Point guard was supposed to be the Celtics weakness last year. They had a second-year player without a jumper, a journeyman who could shoot but who wasn’t a real point guard, and a rookie who wasn’t going to play. They won 66 games and a championship anyway.

Now it’s 2008, and Rondo is no longer an unknown commodity. House is what House is and it’s far better than people give him credit for (still), and now Pruitt looks like a player. The Celtics backcourt is in good shape.
 
Just remember: It’s all about flow.

Paul Flannery covers the Celtics for WEEI.com.