The Washington Bullets were still up in the air today over their sensational rout Thursday night of the Philadelphia 76ers. After circling fog-shrouded LaGuardia Airport for an hour this afternoon, the Bullets came down to earth tonight in Madison Sqaure Garden, where they were outrun by the New York Knicks, 124-112.

Washington built a 37-30 first-quarter lead on 14 points by Kevin Grevey and six assists by Kevin Porter. The Knicks, however, went to their bench in the second period and wore down the weary Bullets.

"That was my effort, the first period," said Grevey, who finished with 23 points. "You can't use last night as an excuse. "You have to play back to back quite often in this league. But we were tired."

"That was very hard on us, after playing a fantastic game last night," said Coach Gene Shue. "The pace was a little bit too much. I know that (Knick Coach) Red Holzman substituted players in the second period who hadn't been seen for a couple of weeks. He wanted to put pressure on us and he did."

The Bullets had a 42-32 lead early in the second period, but the Knicks reeled off 12 straight points, all but two by substitutes. Porter and Grevey were replaced when it became 42-38. By the time they returned, New York was ahead to stay.

"I had a decision to make," Shue said. "They were playing great, but if you don't give them rest . . . You have to give them rest during the game and I tried to pick the right spot."

The Knicks scored 41 points in the second period as they forged a 71-66 halftime margin. The bench accounted for 32, with Mike Glenn scoring 12 and Mike Woodson 10. For the game, New York's substitutes had 51 points, with Glenn leading the team with 21.

The Washington bench scored 26 points, with Mitch Kupchak getting 19. The Bullets had the game's three leading scorers -- Ivin Hayes and Grevey with 23 each and Porter with 22.

"That's the key to this game -- to have a good bench," Porter said."They don't have the strongest bench in the league, but it's a good one. They picked up a lot of loose balls and steals. When they're coming down three on two, and two on one, they're going to score."

New York shot 55 percent for the game and had the unusually low total of nine turnovers, compared to the Bullets' 51 percent and 17 errors. It was the Knicks' 10th victory in the last 11 games, and there was wonderment both about the size of the crowd (11,092) and its lack of exuberance.

Despite their admitted weariness, the Bullets did not concede defeat easily. Sixteen points down at 100-84 after a drought of almost three minutes early in the fourth period, Washington battled back within six at 108-102. Porter, who had 15 assists, scored three baskets in the surge that made it close.

Washington got possession but Hayes fumbled the ball. Ray Williams stole it and Sly Williams stuffed the fast-break basket. After Kupchak blew a layup, Bill Cartwright scored over Hayes for a 10-point margin.

Hayes' layin off a feed from Greg Ballard and a spinning fast-break layup by Porter again closed it to six at 112-106, but three-point plays by Campy Russell and Ray Williams removed any remaining doubt from the outcome.

There was a scuffle between Porter and Ray Williams near the end of the first half that probably looked more serious to television viewers than it actually was. Williams fouled Porter, who made the first shot. Then Williams yelled at Porter and was pushed away by teammates, with Holzman finally sending in a substitute.

"I was explaining something to the referee and Kevin Porter walked off the line to interfere," Williams said. "I talked to him a little bit, just using a psychological tactic."

"There was simply a foul called, and before I know it Ray Williams is telling me next time it'll be a foul worth calling," Porter said. "I don't have a problem with him. He has a problem with me."

The Bullets have a problem with the Knicks, though. The record for the year reads 0-4, with two games left in Landover.