O’Neil Glenn made quite a first impression on Tatiyiana McMorris.

“I had never seen a coach that big,” the Kennedy senior said. “It was a little scary.”

Glenn is not a typical girls basketball coach. He was a standout lineman at Maryland and played briefly in the NFL before starting his new career.

“I’m still learning,” said Glenn, who will lead the second-seeded Lady Knights into their first PSAL AA championship game on Sunday when they face eight-time defending champion Bergtraum, the No. 1 team, at Madison Square Garden at 5 p.m. The game will also be on MSG Network. “But it’s become an obsession.”

His opposing coach can relate. Ed Grezinsky was the head football coach at Lincoln after serving as the team’s defensive coordinator when the Railsplitters won a PSAL title. He has since built the most powerful program in league history and thinks Glenn may be on his way to providing an annual challenge.

“I always used to see him around the Kennedy football team when I was at Lincoln,” Grezinsky said of Glenn, who led the Bronx school to a state title in 1984. “He’s obviously had a lot of success with his playing career, so as long as he brought that same work ethic to coaching, I thought he’d do well.”

And Grezinsky doesn’t think it’s a coincidence that the two men who have more football experience than basketball are in the championship game.

“That intense, football mentality helps when you’re coaching basketball,” Grezinsky said.

Glenn agrees.

“If you want to win, you’ve got to be tough,” said Glenn, who has his team do some of the same strength and speed drills the football team does. “It took some time for me to get the best out of them.”

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Lincoln’s Devon Peterson was among those chosen for the Jordan Brand Classic Regional Team yesterday and will play at the Garden on April 21.