"He was the greatest friend you could ever imagine," Crystal said. "It's very hard to talk about him in the past, because he was so present in our lives. [...] He was the brightest star in the comedy galaxy."
"Robin Williams, what a concept," Crystal concluded his moving segment. The Emmys also featured a reel showing the comedic star in his diverse roles, but all revealing his unique comic streak.
WATCH Billy Crystal's tribute above.
Robin Williams died a fortnight ago at his home near San Francisco, at the age of 63. He had won two Emmy awards himself in the 1980s, and had been nominated eight times in total.
His most recent work was on TV show 'The Crazy Ones' alongside Sarah Michelle Gellar.
It is only a year since Robin Williams was on stage himself at the Emmy Awards, paying tribute to his 'Mork and Mindy' writer Jonathan Winters.
"Johnny turned out the lights, but he sure burned bright while he was here. Thanks for the spark, big guy," Williams concluded.