Forward Michael Cooper scored 30 points as Los Angeles overtook host Phoenix for their fourth straight win.
Norm Nixon had 23 and forward Jamaal Wilkes 22 as the Pacific Division-leading Lakers (22-7) won for the 20th time in their last 23 games.
Phoenix (15-11) had its three-game winning streak snapped plus a nine-game streak on Christmas Day.
The Lakers won without center Kareem Abdul-Jabbar, who has a sprained tendon in his right ankle. The 7-foot-2 veteran suited up, but did not play. It was the third time this year that Los Angeles has won without Abdul-Jabbar in the lineup.
Cooper said second-half patience was the reason the Lakers won.
"We cut their lead down to five at the half, and our coach (Pat Riley) told us to take things easy and not try to make up the difference all at once," he said. "We played deliberate basketball and kind of whittled away at them."
Trailing, 60-55, at halftime, Los Angeles used nine third-period points from Nixon to close the deficit to 82-80 entering the final quarter.
Nixon then scored four points before consecutive baskets by Cooper gave the Lakers their first lead since the opening period, 88-86, with 7:29 remaining.
After Phoenix went ahead, 91-90, on forward Alvin Scott's free throws with five minutes to play, Cooper scored four points in 59 seconds and the Lakers led, 96-91.
Suns forward Len (Truck) Robinson's lay-in made it 98-97 with 1:40 to go. But Nixon sank a fall-away jumper 20 seconds later, center Jim Brewer added a dunk and Wilkes' free throws down the stretch clinched the victory.
Center Alvan Adams and guard Dennis Johnson each had 19 points for Phoenix, with Robinson scoring 17. Adams had 10 of his points in the first period and Robinson's layin at the buzzer put the Suns up, 30-28, heading into the second quarter.
Laker forward Earvin (Magic) Johnson made five of his 18 points in the final 35 seconds of the first half, leaving Phoenix ahead by five at halftime.