The Philadelphia 76ers built a 23-point lead in the third quarter, then held on for a 107-104 victory over the scrambling Los Angeles Lakers tonight to even the NBA finals at one game apiece.

In one of the most splendid comebacks in any championship series, the Lakers, trailing by 18 points at the start of the last period, cut their deficit to 105-104 with 31 seconds to play as Kareem Abdul-Jabbar scored the last of his game-high 38 points.

Bobby Jones' foul-line jumper with seven seconds to play -- just before the 24 second clock ran out -- was the Sixers' killing blow. A wild 35-foot shot at the buzzer by Norm Nixon was not close.

The combatants meet next in Philadelphia on Saturday afternoon.

The Sixers were led by the trio of Darryl Dawkins (25 points), Julius Erving (23 points) and Maurice Cheeks (23 points on 11 of 13 shooting plus 10 assists).

"Everybody seems to act like we're going to win four straight," warned the Lakers' Norm Nixon before this second game. "It's not going to be that easy."

Indeed, it was not. Sixer Coach Billy Cunningham was far closer to the mark when he insisted that "this Series will be decided by the team that makes the most and best strategic adjustments to what the other is doing."

The first half of this war was a textbook example of how one NBA team can, with two days off, come up with a perfect countering ploy. On the other hand, the Lakers were loath to change any of the tactics of their 109-102 win Sunday -- and they paid for it to the tune of an 18-point, 59-41 intermission deficit.

On Sunday, Darryl Dawkins, over burdened with guarding Kareem Abdul-Jabbar, got into foul trouble early. Julius Erving, doubled-teammed when he touched the ball in the halfcourt offense, was held to 20 points. And the 76er guards -- constantly presented with open jumpers by the gambling Lakers -- shot less than 40 percent.

How quickly matters can change.

The Sixers took Dawkins off Abdul-Jabbar so that he could get "into the game. Man, did the guy from Lovetron get going.

On defense, Dawkins took it into his head to eat alive any Laker, other than the big one, who dared roam underneath. Jamaal Wilkes -- The Backdoor Man -- got stuffed twice in five seconds and contracted a severe case of the "where-is-Darryl?" disease before shooting.

Dawkins was as tough a dude for Abdul-Jabbar to cover as the gaint could imagine. The 7-foot-2 Laker got his customary 16 points in the first half, but it was Dawkins -- dunking like a true Interplanetary Funksman --who wracked up 17 points and inspired the Sixers with his fury at both ends.

Dawkins' best was a flying-through-the-lane, left-handed, windmill slamdunk follow up on a rebound that he interecepted two feet above the iron. Crunch!

The Lakers' secret weapon -- one not devined yet around the NBA -- is the quick third-quarter blitz, just like the 12-0 run that crippled the Sixers on Sunday. In 14 playoff games, L.A. has won the third period 13 times

It looked, at first, as though Philadelphia had found a solution for this Laker art form, too. With Dawkins changing his offense from earth-shaking, headbreaking dunks to jumpers from the circle that even had the Forum crowd gasping in appreciation, the Sixers lead grew to 68-45.

The Sixer defense tonight, however, was even good enough to hold the Lakers at bay in their favorite quarter on their home court. The hosts -- who have been to the NBA finals nine times but only won one -- made a nice third-period push (15-5) to cut their deficit to 73-60, most of the damage done by Abdul-Jabbar simply refusing to be denied. But, by the start of the last period, the Sixers were just where they had been after that decisive first half, leading by the sort of 18-point margin (89-71) that should never be erased in 12 short minutes.

When The Doc smacked a Norm Nixon jumper back in Nixon's face, the little guard simply caught the ball in midair and flicked it into the basket from 13 feet out to make it 99-98 at 2:22.

Dawkins powered under and drew a foul from Abdul-Jabbar, then canned both free throws. On the next posses the Sixers battled a pass free and Cheeks flew in for a fast break dunk.

That five-point lead should have been enough with only 1:11 left -- except against Adbul-Jabbar, the human point machine. Sky hook for two. Dr. J back at you for a big jumper at the other end, then his majesty Kareem for a turnaround jumper, and yet another sky hook for his 37th and 38th points and a mere 105-104 Philly lead with 31 seconds left.

At this heart attack juncture, the Sixers worked the clock down, searching for a shot just before the 24-second clock ran out.

And that, miraculously, is just what they got. Just as the 24-second clock was about to buzz, Jones put up a soft 14-footer as Abdul-Jabbar took a run at him.

The shot went down the hole with seven seconds left for a 107-104 lead. That was the death knell.

Nixon gunned for a three-pointer but the ball hit only glass. It had been a long magnificent run, but it had died.