Hubie Brown is volatile, rambunctious, and some critics say, even a little flaky.

As a basketball coach, he believes in defense, team play and doing things his way. He teaches, and those who learn to play for him; those who don't are soon gone. Hubie Brown doesn't change his system for you. You change for him.

The new New York Knicks are products of his impact. When he took over the team in the offseason, it was a woefully disorganized group, and Brown made so many changes that the very foundation of Madison Square Garden threatened to shake. Only four players from last season remain on the 12-man roster.

The Garden is rocking with excitement again as fans are getting behind one of the hottest teams in the National Basketball Association. The Knicks have won seven in a row, 11 of 12 and 21 of their last 25 games. They have also won five in a row and 10 of their last 12 on the road, and have moved from the Atlantic Division cellar to the fifth-best record in the Eastern Conference, 35-30. They look like a lock for a playoff spot.

They will try to put more distance between themselves and one of their pursuers tonight when they face the Washington Bullets at Capital Centre at 7:30. The earlier-than-usual start is because the light heavyweight championship fight between Dwight Braxton and Michael Spinks will be shown on Telscreen after the game.

The Bullets and Knicks will have a rematch Saturday night at Madison Square Garden.

The Knicks, who lost their first seven games before beating the Bullets here, are 5 1/2 games ahead of seventh-place Washington (29-35) in the conference. The top six teams make it to the playoffs. The sixth-place Atlanta Hawks (34-32), beat the Bullets, 94-81, in overtime at the Omni Wednesday night and dropped them four games out of contention.

Brown remained patient and kept making changes when the team was struggling. Now, everything has come together.

"Even when we were losing, we kept saying we were a minuscule away from being great and no one lost confidence," Brown said yesterday.

Brown has a proficient scorer in forward Bernard King (22 points a game), two 7-foot centers in Bill Cartwright and Marvin Webster, an enforcer in Truck Robinson, someone to run the show in Paul Westphal and a talented bench featuring Webster, Sly Williams, Rory Sparrow and Louis Orr.

Cartwright is averaging 19.5 points and 8.2 rebounds and has shot 62 percent in the last 25 games. Westphal is averaging 12 points and 6.8 assists in that span and added stability to the Knicks. He was criticized by many two months ago, but Brown stuck with him.

"It's been real fun to see this turnaround," said Westphal. "I was in a situation almost exactly like this my first year in Phoenix. We had a bunch of new players and got off to a slow start, but stayed at it and turned things around in the second half and went all the way to the finals. It can happen if you stick with your program and don't get down on yourselves."

Brown teaches a patterned, controlled offense and an intricate defense, both of which take time to learn. Now those half-court traps, zone presses and switching defenses are confusing opponents.

The Knicks lead the NBA in defense, allowing 97.7 points a game, 2.4 fewer than the second-place Bullets.

"Even if we are not scoring, even if things are going badly on offense, we can always stop the other team from beating us by holding them down," said Brown. "We are starting to believe that we can stop people and win even when we aren't shooting well."

Westphal, who became a starter in mid-January when Edmund Sherod was injured, built a reputation as one of the top one-on-one players in the league. But he has changed his focus.

"We feel we can keep the defensive pressure on the entire game," he said. "We're confident that if we do that, at some time we can crack the other team."

After this weekend's games the Bullets will have only one game left with Atlanta and none with New York, so they will have to depend on help from other teams if they are to make the playoffs.