Kevin Porter and Kevin Grevey offset a brilliant 39-point performance by Kansas City's Otis Birdsong last night and led the Bullets to a 107-103 victory over the Kings at Capital Centre.

Grevey, suffering from bronchitis for the last three days, came off his sickbed and scored 21 points, nine straight as the Bullets broke away from a 91-91 tie midway through the final period.

Porter came off the bench for 18 points and six assists. He assisted on all four of Grevey's field goals in his nine-point run.

Joe C. Meriweather made a short hook shot to tie the score at 91. Grevey countered with a baseline jumper off a pass from Porter. Elvin Hayes, who scored 24 points, then knocked the ball away from Kansas City rookie Hawkeye Whitney. Porter picked it up and fed Grevey for a fast break and a 95-91 lead.

Phil Ford sank a 12-footer to cut the lead to two, but Grevey answered with a layup after Porter had penetrated the defense and passed off to him. Grevey also was fouled by Sam Lacey and made the free throw.

Grevey concluded his spurt with a jump shot after Porter found him free in the corner. With that, the Bullets had a 100-93 lead with 4:12 to play.

Those were the only four shots Grevey took in the final period. He was so out of breath by then that he had to be taken out of the game. His doctor had advised him not to play. But, Grevey said, had he not the Bullets would have had only eight players and, after taking a sauna and resting all day, he felt he could play at least a little bit. He had no idea he would play 38 minutes.

"I was weak the whole game," Grevey said, "but I had enough energy to raise my arm."

The Kings closed to 104-100 on a three-point play by Birdsong with 1:14 remaining, but Greg Ballard's jump shot, after a pass from Porter on an inbounds play, got the lead back to a safe six points.

Birdsong scored most of his points against Grevey. Scott Wedman helped with 24 points, but the rest of the Kings was pretty common.

"Birdsong and Wedman can keep anyone in the game," Grevey said. "But we held them down when we had to and we got the key baskets. Kevin would rather pass the ball than shoot and I just tried to get to a spot where he could get the ball to me."

Ford played poorly, with only eight points and five assists. He committed five turnovers and was in foul trouble much of the game, which helped the Bullets beat the Kings for the first time since the 1977-78 season. Only 5,981 were present to see it, though.

The Bullets had a 10-point lead early in the third period.But Birdsong, the National Basketball Association's fourth-leading scorer with a 26.8 average, scored six straight to cut the lead to 67-63.

The Bullets still were on top, 69-65, when Ford's backup, Lloyd Walton, was called for traveling as he tried to score against Porter Kansas City Coach Cotton Fitzsimmons, feeling a foul should have been called on Porter, stormed off the bench screaming at official Hue Hollins, pushing his assistant, Frank Hamblen, aside to run onto the court.

For his effort, Fitzsimmons caught up with two technical fouls and was ejected.

Grevey made the two free throws for a 71-65 lead, but the ejection fired up the Kings. They scored seven straight points, four by Reggie King and three by Birdsong, to go ahead, 72-71.

The lead changed sides or the score was tied six times after that before Grevey's spurt.

The victory improved the Bullets to 11-14, with a game tonight in Indianapolis against the Indiana Pacers (WDCA-TV-20 at 7:35).