Magic Johnson 1987 Finals: Gm 4 vs. Boston Celtics, "Skyhook Game"

A 12-foot running hook shot by Earvin (Magic) Johnson with 2 seconds remaining tonight enabled the Los Angeles Lakers, trailing by 16 points in the third period, to edge the Boston Celtics, 107-106.

The victory gave the Lakers a 3-1 lead in the four-of-seven-game series and a chance to dethrone the Celtics here Thursday night.

It was only the Celtics' fourth defeat in the last 98 games at the Boston Garden since they were beaten in Game 6 of the 1985 National Basketball Association Finals by the Lakers. Two of those defeats have been by the Lakers, who snapped a league-record string of 48 games last Dec. 12. Stage Is Set

The stage for Johnson's dramatic winning basket was set with 8 seconds remaining when Kevin McHale fouled Kareem Abdul-Jabbar, sending the 7-foot-2-inch center to the line for two free throws. He made the first and missed the second, but when McHale tried to grab the rebound, he lost it out of bounds, giving the Lakers possession.

After a timeout, Cooper passed the ball inbounds to Johnson on the left side. He drove into the lane and added the 2 points that brought his game total to 29 to go with 8 rebounds and 5 assists.

The Celtics, with the last shot, put it in the hands of Larry Bird, who had given his team a 106-104 lead 10 seconds earlier with a 3-point basket from the left corner. Bird's final shot from the wing was too long.

''Worthy was our first option, with seven seconds left, if Michael could have gotten him the ball,'' said Coach Pat Riley of the Lakers of the winning play. ''Johnson was our second and then Kareem.'' Johnson Sets Pick

As Cooper was passing inbounds, Johnson set a pick for James Worthy. Dennis Johnson, who had been guarding Magic Johnson, switched over to Worthy, and McHale came over to pick up Magic Johnson, who received the pass. As Johnson was dribbling, looking for the shot, Robert Parish came over to help out. It was here that Johnson drove the lane and hooked the ball over both Celtic big men.

''I could have shot the jumper,'' said Johnson, ''but I'm not a jump shooter. If I would have tried it, McHale might have blocked it. When you have a big man on you, it's always a good idea to take the ball to him and that's what I did before I hooked it over him.''

The winning basket was Johnson's only field goal of the final period, in which the Lakers went to the free-throw line for 14 shots and made 10.