Nick Young scored 28 points off the bench, while Jodie Meeks hit six 3-pointers and finished with 26 for Los Angeles, which now embarks on a 12-day road trip.
"This is hard," said Young, who missed a potential tying 3-pointer with 10 seconds left. "We're losing, and we're losing players daily. It's frustrating, but we've still got to get up and play basketball. Nobody wants to get embarrassed. You've got to still take pride in that Lakers uniform."
Pau Gasol scored 20 points and grabbed 12 rebounds playing with a sore big toe.
"It wasn't like our energy and focus weren't there," Gasol said. "The defense needs to improve drastically, that's for sure."
Kendall Marshall, who was drafted 13th overall by Phoenix and played 48 games as a rookie last season before being traded in October, had 10 points and 16 assists.
Marshall is averaging 13.0 points and 12.0 assists while starting the last six games for the Lakers, who have lost six straight on the road. The latest defeat in that stretch came to the Los Angeles Clippers at Staples Center on Friday.
Phoenix (21-16) begins a five-game homestand after closing a 1-4 road trip with three straight defeats, including Monday's 98-96 overtime loss to the New York Knicks.
Goran Dragic had 28 points for the Suns, who are 2-5 since Eric Bledsoe went down with a knee injury that will keep him out 4-6 more weeks after surgery.
"It's a little bit harder now with Eric out," Dragic said. "It's much easier when you're playing together and you have two ballhandlers. But it is what it is and I have to keep my head up."
Gerald Green finished with four points on 2-of-16 shooting for Phoenix, which shot a season-worst 35.5 percent from the field.
"We didn't make shots," first-year coach Jeff Hornacek said. "Don't know if it's because it's the end of the trip."
Miles Plumlee remained a bright spot, though, finishing with 12 points and 11 boards. He's averaging 10.0 points and 9.1 rebounds in about 28 minutes while starting every contest.
Plumlee played a total of 55 minutes over 14 games for Indiana as a rookie last season before being traded to Phoenix along with Green in July.
"We're very confident throwing the ball in the post to him," Hornacek told the team's official website. "He's got a quick move. He's strong, so if he gets bumped he doesn't fall out of position. He's turned into a great player for us."
The Suns have won seven of nine at home and will be seeking their third win over the Lakers this season. Dragic had 31 points in a 114-108 win Dec. 10, while Plumlee had 17 points and 20 rebounds in a 117-90 victory Dec. 23. Green had six 3-pointers and 22 points off the bench in the last meeting.
Nash, a two-time MVP with Phoenix, hasn't played in either meeting due to a back injury.