"Thirty-five years after he stopped fighting, he's still the champion of the world," he opened, after explaining the beauty he had witnessed all day from family, friends and fans.
Crystal then spoke about the 42-year friendship he had with Ali that began when he was hired to perform at an event honoring the boxing legend more than four decades ago.
"Ali had just beaten [George] Foreman, Sport magazine made him their man of the year," Crystal said, adding that at the time, he did a great impression of Ali and his friend Howard Cosell.
"I couldn't believe it, my first time on TV and it was with Ali," he said. When Crystal arrived to the big event honoring Ali, he saw him for first time in person and said, "I couldn't stop looking at him.... He was funny, he was beautiful.... He was so much more than a fighter."
The actor, 68, said "the audience exploded" with laughter when he did his Ali skit. Then, "The Greatest" went up to Crystal and gave him a hug, saying "You're my little brother."
"He always called me that till last time I saw him," Crystal explained.
Ali was generous with his time for Crystal, the comedian said. Dinners, charities, whatever he needed.
"Here's the most famous Muslim man in the world, honoring his Jewish friend," he said. "I had so many funny moments with him."
But there were serious moments too. One time, Ali invited Crystal to run with him at a prestigious country club. But they didn't allow Jews there, so Ali vowed to never run there again.
"And he didn't," Crystal said.
"I've labored to come up with a way to describe the legend," he continued, before saying he'd settled on a lightning bolt.
"On the moment of impact, it lights up everything around it," he said. "His intense light shined on America. We were able to see clearly injustice.... Ali forced us to take a look at ourselves."
Crystal closed his remarks: "He is gone, but he will never die, he was my big brother."
The three-time heavyweight champ died last Friday at the age of 74 after battling Parkinson's disease for more than 30 years. His cause of death was "septic shock due to unspecified natural causes," family spokesman Bob Gunnell said.
Ali will be buried at the Cave Hill National Cemetery in Louisville.