Newly minted centenarian Esther Semiday celebrated her 100th birthday Friday at an East Harlem senior center—and opened the festivities with a solo.

“She loves the karaoke,” senior-center Director William Dionne said of Semiday, who wooed the crowd with a traditional Spanish song. “She’s feisty and spirited and speaks her mind. She’s so celebratory of life.”

Semiday, who also boogied to live music during the packed celebration, told The Post that turning 100 felt “very, very wonderful.

“When I was small, I used to work hard. I think about being good all the time. For me, 100 years is very, very happy,” she said.

At one point, she blew out candles atop a vanilla guava cake.

The Puerto Rican native, whose birthday was Feb. 1, has lived in Harlem for more than 75 years.

Her family also has a second 100-plus in their ranks—Semiday’s sister Virginia, who is 104.

Semiday, a great-grandmother, told The Post that she never lets her age stop her from lending a hand.

“Everyone that helped me, if they want me to do something, and I can do it, right away, I try to do it,” she said.