NBA

ATLANTIC GRITTY

The Knicks arrive at the season’s midpoint tonight to play their season’s biggest game.

It’s Knicks against Nets at the Garden tonight: the battle for the Hudson and, for once, the battle for the Atlantic. It’s playoff time in January, time for the Knicks to show they plan to be around fighting until April.

Several Knicks called it “a big game.” Eddy Curry called it “a must win.” This border war has been all Nets for five years; Jersey is 16-4 since Jason Kidd arrived from Phoenix. Now the young Knicks finally are in position to kick some sand in the bullies’ faces.

Despite a 17-23 record, the Knicks trail the Nets (18-20) by two games in the Atlantic Division race. On the eve of their first meeting of the season, Knicks coach/president Isiah Thomas bestowed only respect on the Nets, winners of four of the last five Atlantic titles.

“They’re the class of the division,” Thomas said. “They’ve been the class of the division for a long time. It’ll be a good test for us. It’ll be a good game.

“They’re the team that probably can make statements,” Thomas said. “We’re not in a championship level yet; they’ve had guys who played in championship games. They know how to get up for big games. They know how to make a statement. We’re not in the statement business yet.”

Said Nate Robinson: “They’re right across the water, so it’s a big game for us. We definitely got to get a win.”

For a change, the Nets are the ones in turmoil, with off-the-court distractions. Kidd is going through a painful, public divorce from wife Joumana and the team has its impending divorce from New Jersey.

But the Nets, who held a lavish press conference in Brooklyn yesterday to announce their prospective arena’s new name, are starting to find themselves after an awful start. They’ve won seven of nine, creeping to two games below .500.

“More than it being the Nets-Knicks, the fact is it’s a big division rival,” David Lee said. “It’s going to be a very important game for us.”

These teams don’t like each other. The Nets always have been jealous of the Knicks because of the fan and media attention. The Nets-Knicks preseason game was an ugly affair, resulting in chippiness in the fourth quarter after Mikki Moore’s hammering of Steve Francis spawned a couple of verbal altercations. At the buzzer, Thomas and Nets assistant Tom Barrise shouted at each other while Jersey coach Lawrence Frank walked off, refusing to acknowledge or shake Thomas’ hand.

“Things got a little physical,” Lee said. “Both teams didn’t want to back down and they knew it’s going to be a rivalry.”

The Nets know the Knicks aren’t playing dead like past years.

“The importance is it’s significant on both sides,” the Nets’ Cliff Robinson said. “I’m sure they feel the Atlantic is still wide open and they have a chance to win it.”

The Knicks, who overcame a rocky first six weeks, own what the Nets never had, even during their Finals berths – an All-Star caliber center in Curry. And now Stephon Marbury has emerged as a defensive demon and likely gets all of Kidd tonight.

“We survived . . . and as a team we’re playing much better basketball than at the start of the season,” Thomas said. “That’s how you measure: Getting better week to week, month to month.”

Still, Thomas positioned his Knicks as underdogs.

“Our job is to one day be where they are and take what they have,” he said. “We still have a ways to go.”

marc.berman@nypost.com