Kaka scored the second goal in the lopsided victory after some good work by team-mate Ronaldo on the left.
He teased the Betis defenders, drawing them close before picking out Kaka breaking into the penalty area.
The Brazilian took two touches to set himself before threading a right-footed shot into the right corner just before the hour mark.
Kaka, who has struggled with injuries since Real signed him for £56million in the summer of 2009, was subbed soon after and came off the pitch to a standing ovation.
"The standing ovation I got made me happy," he told the club's official website.
"It's important for me to keep improving. I think this is the third match I played next to Ozil. He is a very intelligent footballer. It's easy to play with him.
"Competition on a squad like ours is positive because it keeps us all awake."
Real's 4-1 win over Betis will also be remembered for striker Gonzalo Higuain's third hat-trick in his last four matches.
"Higuain has scored nine goals in four games and that's great," Kaka said.
"He should be congratulated. We're all happy with his streak. The coach [Jose Mourinho] now has a problem."
Meanwhile, Ronaldo made his 100th appearance for Real against Betis. The Portuguese has scored an incredible 95 goals in his three seasons at the club.