New York was in a Long Island state of mind last night. While singer/songwriter Billy Joel began the third year of his Madison Square Garden residency, comedian Jerry Seinfeld kicked off his own yearlong residency, dubbed “The Homestand,” at the Beacon Theatre where he will perform monthly.

Seinfeld emerged on the stage to thunderous warm applause.

“Look at this — it happened! What an impressive accomplishment on your part to get here,” he said as he grabbed the mic. “I’m sure some of you were dragged against your own will. Some of you are saying, ‘I see this guy every night on TV, do I have to go all the way to the Beacon? Are the other three going to be there? No? Then what’s the big deal?”

Being a married father of three, Seinfeld has even let domesticity creep into his act.

“Being married is like being on a game show and you are always in the lightning round with your wife who is the returning champion,” he said. “I’ll take movies I think we saw together for $200. ‘I’m sorry Mr. Seinfeld, you didn’t win the weekend sex package but please remember to take this garbage with you on your way out.’ ”

For an encore Seinfeld, 61, addressed the crowd with heartfelt thanks.

advertisement | advertise on newsday

“I’m excited about this new experience. I’ve been standing on stages like this doing comedy since I was 21,” he said. “It’s my favorite thing to do.”

Since it was opening night, Seinfeld treated the crowd to an improvised Q-and-A.

When asked what his favorite “Seinfeld” episode was, he said, “I have more favorite moments rather than episodes. I like when George poisoned his fiancee, I like when Kramer hit the golf ball into the whale’s blowhole and I like when I stole the rye bread from the old lady.”

Carolyn and Dominick Tringali came in from Seinfeld’s hometown of Massapequa to catch opening night.

“My daughter got me tickets for Christmas. She had her whole office trying to get a pair on the computer,” said Carolyn, 51. “Next I’ve got to go see Billy Joel!”