At least for one night, Gay looked comfortable in that role.
Gay scored 29 points and guarded Gordon Hayward aggressively in the final three quarters, and the Kings overcame Cousins' absence to beat the struggling Utah Jazz 101-92 on Monday night.
"A lot of times I've been settling and sitting back thinking I have him," said Gay, who made 10 of 19 shots. "We've kind of been a tandem so far this year, but he's not out there, so I have to be aggressive on both ends."
Darren Collison added 16 points and six assists, and rookie Nik Stauskas scored a season-high 15 points to go with eight rebounds as Sacramento pulled away in the fourth quarter for a rare win without its franchise center.
Cousins sat out for the sixth straight game because of viral meningitis, which will sideline him at least the rest of the week. The Kings are 2-4 without Cousins this season and had lost 17 of their previous 18 games when he doesn't play.
"We're a great team with him, but we're also a great team without him. We have to believe that to win games," Gay said.
Hayward scored 12 of his 19 points in the first quarter, and Alec Burks returned from a left shoulder injury to score 16 points for the Jazz, who have lost nine in a row under first-year coach Quin Snyder.
Sacramento outshot Utah 47.3 to 40.5 percent.
"We are just going to have to put it all together," said Jazz guard Trey Burke, who scored 13 points. "If we play like we did tonight on the defensive end, I am sure our offense is going to come around."
The Kings scored 12 straight points early in the fourth to take an 80-70 lead. Utah rallied with a 7-0 run, and the teams traded baskets over the next few minutes.
Stauskas put Sacramento in control for good when he converted a twisting layup while getting fouled by Rodney Hood. The three-point play put the Kings up 89-79 with 3:22 remaining.
Kings coach Michael Malone joked that Stauskas "became a man" in the NBA with the late-game performance. The eighth overall pick out of Michigan just said he felt like his old self again after an early season slump.
"I feel like this is all I really needed," Stauskas said.
The victory kept the Kings (11-10) above .500 and slowed a slide that started when Cousins got ill, which is expected to keep him out longer than the team originally anticipated. Malone said that Cousins will need time to practice and work back into shape whenever he is cleared to resume basketball activities.
Without their big man in the middle, Sacramento started slow again.
Utah (5-16) seized the momentum early, with Hayward having his way in the first quarter to the help the Jazz go ahead 31-23. But the Kings came back in the second quarter with their defense, getting out in transition for easy baskets, including fast-break dunks by Gay and Ben McLemore in the final minute.
Sacramento led 55-49 at the half.
Jazz: It was the first of four meetings between Utah and Sacramento this season. The Jazz won last season's series 2-1. ... Utah had 20 assists and 13 turnovers.
Kings: Lead assistant coach Tyrone Corbin, the former Jazz coach, injured his Achilles tendon working out last week. He shared hugs and handshakes with some of Utah's staff outside the Kings' locker room but will not be on the bench until his injury progress. ... Sacramento had 18 assists and 17 turnovers.
Jazz center Enes Kanter was called for a technical foul with 4:34 remaining after throwing his mouthpiece into the stands, drawing boos from the crowd. Gay missed the free throw.
Rapper Tyga performed at halftime with Anjali Ranadive, the daughter of Kings owner Vivek Ranadive. She goes by the stage name Anjali World.
Jazz: Host San Antonio on Tuesday.
Kings: At the Los Angeles Lakers on Tuesday.