EAST RUTHERFORD, N.J. — Through all the ups and downs — okay, mostly downs — of the first 72 games of the Nets’ season, it now, amazingly, comes down to this: Win as many games as the Hawks over the next three weeks, and New Jersey’s playoff streak hits seven. Fail to do so, and it’s Lotteryville.

Realistically, a playoff berth would only extend the Nets’ season by four games, and I mean exactly four games. New Jersey’s first round opponent would be the mighty Celtics, a team they haven’t come close to beating in three tries.

Nonetheless, it’s a healthy goal for the new-look Nets. And in the wake of Wednesday’s 124–117 win over Indiana at the Meadowlands, it seems a more realistic possibility than ever. The Nets can strike a death blow to the Pacers’ hopes by beating them in Indiana again tonight. But even if they fail, they’re unlikely to fall behind Indy: It’s a basically a race to the finish against the Hawks.

Looking at the remaining schedule shows why the Nets have a great shot at the postseason. New Jersey’s last three opponents should be all but automatic wins — Charlotte and Milwaukee, because they’re Charlotte and Milwaukee; and Boston on the season’s final day, because the Celtics are likely to be resting their starters for the playoffs.

That leaves the seven-game stretch between now and the final week as the most critical stretch of the season, starting with tonight’s game in Indy. None of them are guarantees: After the Pacers, it’s Phoenix, Philadelphia, at Detroit, Toronto, at Cleveland, and at Toronto. But if the Nets can win three of the seven, they’re probably safe. Take four, and they become close to a lock, as the Hawks would have to finish on an 8–4 tear to trump it.

Since I’ve been a Nets pessimist for much of the season (and can you blame me?), you may be surprised to see my tune has changed. Win three out of seven against decent competition? This team? Surely I jest.

But the difference between the Nets of the past few weeks and the Nets of most of this season is a fairly obvious one: They can score.

This is a bit of new territory for the Nets, who have become accustomed to scratching out wins with middling-at-best offense and tenacious defense over the past several years. With defensive aces of years past such as Jason Kidd, Kenyon Martin, and Jason Collins on other rosters, that’s no longer the case, and the Pacers showed it on Wednesday.

But the Nets won anyway, because the addition of Devin Harris and the return of Nenad Krstic had made this team so much more potent offensively.

You’ll have to forgive Nets coach Lawrence Frank, because this is uncharted territory for him. His instincts run much more toward Bobby Knight than Mike D’Antoni, and after the game he talked about his theory that the team who defends better normally wins. But on a night where neither side lifted a finger on defense, all he could offer as a follow-up was a sheepish, “I guess we defended slightly better … maybe.”

No, the reason the Nets won is they finally have a half-court offense worth talking about, so they can win even when the defense isn’t sharp. This was the elephant in the room that seemingly nobody wanted to discuss during the Kidd years, especially toward the end — that for all his brilliance in transition, he was very ordinary in the set offense. Just ask the Mavs. Harris, in contrast, is the kind of lightning quick penetrator the Nets haven’t had since Stephon Marbury. (As an added plus, that’s about where the similarities between the two end).

With Harris’ ability to turn the corner on pick-and-rolls and Frank’s newfound willingness to set him free to do just that — something Avery Johnson couldn’t or wouldn’t do in Dallas — it’s a brave new world in Jersey. No longer does the offense degenerate into Vince Carter or Richard Jefferson hoisting a long J at the end of the shot clock. In fact, Harris was so effective in Wednesday’s first half that Carter became a virtual bystander.

Instead it was Josh Boone who became the unlikely scoring machine, as Harris’s penetrations consistently ended with a dish to Boone for a lay-up or a dunk. He finished with a career-high 26 points against the Pacers, and it’s no accident the two highest scoring games of his career have come in the past two weeks.

“Josh is always a byproduct of our ball movement,” Frank said. “If he scores that means the ball’s moving. Devin did a good job of finding the open man … and [that’s when] guys like Josh and Bokie [Nachbar] have big nights.”

The other positive for the Nets down the stretch is the return of Krstic. Though he’s been back in uniform since early February, only recently has he flashed his old form. Krstic had back-to-back double figure games this week, including a 22-point outing against the Knicks, and is shooting 51.1% from the floor in March.

“He’s played better and hopefully it’s something he can build on,” Frank said. “Some of it is just from a confidence standpoint, and the next part we need to come along his defense, especially from the weak side.”

Defense, schmefense. Instead, check this out — a lineup of Harris, Jefferson, Carter, Krstic, and Boone has five players the opposing defense has to guard. Yes, all five! What a concept, huh! There’s no Jason Collins or Antoine Wright in this lineup wearing a neon “Leave me to double Carter” sign hanging around his neck.

As a result, the Nets season is officially revived. They’ve won five of eight since returning from their disastrous tour of the Southwest Division, with two quality wins (Utah and Cleveland) and only one true dud (a 112–96 loss to the Bulls). In six of the eight games, they’ve scored 104 points or more in regulation time — something they managed seven times in 52 games before trading for Harris. It’s possible it ends up being too little too late, and that the rough schedule over the next seven games proves too much for these Nets to overcome. But either way, folks at the Swamp have plenty more to look forward to than it seemed just a couple of weeks ago.

jhollinger@nysun.com