Kevin Durant scored a game-high 38 points for Phoenix in what was both teams' in-season tournament opener.
The Suns led 96-89 at the end of the third quarter after Durant scored nine points in a span of 71 seconds.
But the Lakers opened the fourth quarter with an 11-0 run to take the lead and ultimately held on.
After missing Wednesday's game at Houston with a hip injury, Anthony Davis added 18 points for the Lakers, who won on the road for the first time in six tries.
Both teams now have a 4-5 record this season, with the Suns having played without Devin Booker (calf) for the seventh time in eight games.
There were a total of nine NBA games played on Friday, all part of the league's new in-season tournament.
Karl-Anthony Towns scored 29 points as the Minnesota Timberwolves came from behind for their fifth straight win, beating the San Antonio Spurs 117-110, despite 29 points from number one draft pick Victor Wembanyama.