NEW YORK -- Boston Celtics head coach Brad Stevens held back tears throughout an emotional pregame press conference on the same day his former Butler player, Andrew Smith, passed away at age 25 after a long battle with cancer.

Smith was diagnosed with non-Hodgkin lymphoma in January, 2014. Stevens skipped a game last week to visit his former player in the hospital after the big man's health took a turn for the worse.

"The last week's been tough," Stevens said Tuesday at Madison Square Garden before a road tilt with the New York Knicks. "I was happy that I got a chance to say goodbye. And this is really about when you coach somebody, you get a lot more out of coaching them than they do from you. And that's that. I could go on and on and it wouldn't do him justice. He was special. He was tough. He set a great example."

Earlier in the day, Stevens tweeted for the first time in almost a year: "To the toughest guy I ever met - Thank you, Andrew. We love you and will always be inspired by you."

Asked what made Smith so tough, Stevens replied: "Those two years, he got tough as a player. He was a really good player. Found a niche and became one of the more high-achieving guys that I got a chance to coach. But the last two years he's been through a lot. And he just never gave in."

Though the details have not been ironed out, Stevens said he plans to attend Smith's funeral.

"I think we'll figure out how to get in and out," the coach said. "But I'm glad I got a chance to go back last week, and I'm really appreciative of the Celtics and ownership for letting me do that."