Nobody might be more thankful than Sacramento's center for the added help.
"It makes the game so much easier," Cousins said. "It's not such a heavy load on me and Isaiah [Thomas] every night, just having another go-to guy."
With Gay leading the way, Sacramento outshot Houston 48.1 to 41.3 percent and finally showed some signs of defense.
Cousins collected 21 points and 10 rebounds, and Thomas had 19 points and eight assists to help Sacramento hold on to the lead for most of the final 35 minutes.
Gay added five rebounds and four assists. He finished 10 for 20 from the field in a dazzling home debut for the Kings, who had lost eight of their past 10 games.
"The basketball is going to be in my hands a lot," Gay said, "so I'm just trying to keep everybody comfortable and keep everybody happy."
James Harden sprained his left ankle early in the third quarter and finished with 25 points, and Dwight Howard had 13 points and 10 rebounds while battling foul trouble in a disappointing end to Houston's quick three-game road trip. The Rockets lost at Portland on Thursday and won at Golden State on Friday.
Rockets assistant Kelvin Sampson filled in for Kevin McHale all three games following the death of McHale's mother. Guard Jeremy Lin sat out with back spasms and forward Terrence Jones had two points and five assists while playing just 15 minutes because of flu-like symptoms.
It's unclear whether Harden or Lin will be able to play Wednesday against Chicago in Houston.
"It's very, very painful," Harden said of his ankle. "I am trying to get through this, stay positive and focus on getting back."
Sacramento's newest attraction seized the opportunity.
Gay, who came over in a seven-player trade from Toronto last week, had 24 points in the loss at Phoenix on Friday. He started quickly in his first game at home for Sacramento, scoring 14 points in the first quarter, including a series of scintillating drives and dunks that brought most of the announced crowd of 15,606 roaring to their feet.
"It makes my job easier on offense. That's for sure," Kings coach Michael Malone said. "He's so skilled. He's so talented. He makes it look so easy out there. He can score in so many ways."
As Houston's mistakes piled up, Sacramento surged ahead.
The Kings took advantage of 11 turnovers by the Rockets in the first half to go ahead 48-38 late in the second quarter. Houston had six turnovers in the second half.
Sacramento didn't exactly play a clean game, either. The Kings finished with 16 turnovers.
"We still had opportunities to win," Howard said. "But we didn't capitalize on them."
Harden gave the Rockets a bigger scare when he twisted his ankle stepping on Ben McLemore's foot while driving through traffic early in the third quarter. Harden lay on the hardwood for a couple minutes, but stayed in the game to make both free throws -- lifting his left foot in the air while shooting -- before limping to the locker room.
Harden returned later in the quarter, and appeared slightly hampered. The Rockets also struggled to regroup, especially with Howard on the bench in foul trouble.
Sampson admitted he "probably should not have put" Harden back in the game. But he was more frustrated with Houston's effort from the start.
"I didn't think we were ready to play," Sampson said. "I didn't think it was a good effort. We are letting too many of these type of games slip away."
Kings G Marcus Thornton did not play in the first half. He had two points in nearly 7 minutes in the second half. ... Houston had won five of its previous six games at Sacramento. ... Rockets big man Omer Asik, who has been the subject of trade rumors, missed his sixth straight game with what the team has called a bruised right thigh.