The Suns led at half time before slipping to a 110-91 loss against the injury-hit hosts.
The head coach told the team's website: "The second half was terrible. We need to be able to fight over screens.
"We weren't playing great in the first half, we missed some three-pointers we typically make and gave them some life going into halftime with the shot they hit.
"They came out in the second half and turned it up. We gave up 35 points in the third quarter. We're not going to beat anyone by giving up 65 points in a half. We need a better effort on defense and need to be tougher."
The Suns face the Houston Rockets later today.