Ibrahimović scored in his first start back at AC Milan to help them beat Cagliari 2-0 in Serie A on Saturday.
The 38-year-old Ibrahimović netted Milan's second goal in the 64th minute. Theo Hernández put in a cross from the left and Ibrahimović hit it first time into the bottom right corner.
"I feel good, and when you feel good the goals will come," Ibrahimović said. "At the beginning of the game I got a few balls wrong but I need to play to get back in form.
"I know that (manager Stefano) Pioli wants to be careful because he's thinking about my age, but there's no problem because the mind is always the same and the body has to follow."
It was Ibrahimović's 57th goal in 87 appearances for Milan and his first since May 6, 2012 when he netted two against Inter.
The Swede raised his arms in celebration and turned to the AC Milan fans, pumping his fist and encouraging their chants for him.
"Every goal I score, I celebrate like God, that way I feel alive," Ibrahimović said.
Ibrahimović, who helped Milan to its last Serie A title in 2011, has rejoined the Italian club until the end of the season with an option for another year.
He made his first Serie A appearance in nearly eight years last Monday, off the bench in a 0-0 home draw with Sampdoria.
Milan hadn't scored for three straight matches and it was a stroke of luck which ended that run, right at the start of the second half, as Rafael Leão's shot took a massive deflection to loop over Olsen.
The win put Milan four points behind sixth-placed Cagliari.