David Letterman and Jay Leno came up together in the L.A. comedy scene of the 1970s, and when Letterman made his way to television, Leno was a frequent guest on his groundbreaking “Late Night” show.

The relationship soured, however, when Johnny Carson announced his retirement from “The Tonight Show”, with Letterman feeling he deserved to be Carson’s successor while the job ultimately went to Leno, who reportedly schemed his way behind Carson’s desk.

Their friendship never recovered, and when Letterman launched his own talk show opposite “Tonight”, the former friends found found themselves locked in a late-night rivalry that lasted for two decades.

RELATED: David Letterman Says He Should Have Retired Sooner: ‘Nobody Had The Guts To Fire Me’

There appeared to be a thaw a few years back, when Leno and Oprah Winfrey joined Letterman for a Super Bowl commercial, and Letterman opened up about their complicated relationship during his appearance this week on Marc Maron’s “WTF” podcast.

Talking comedy with Maron, Letterman insisted that Leno was a far superior standup comic than he was. “Jay was always the funniest. Without question,” insisted Letterman, 72.

“In Jay’s case, it was not so much joke writing as it was… his attitude was hilarious,” Letterman added. “So whether he had a joke or not, it was funny. And people loved him.”

Looking back, Letterman now sees what happened between them as the result of Leno’s insecurity.

“I’ve always said two things: He’s the funniest person I was ever around; and what we see is a manifestation of deep insecurity. But as a standup, was there anybody [as good?]” Letterman added.

RELATED: Jimmy Fallon Gifted David Letterman Avocado Toast And Isn’t Sure What To Make Of His Response

When asked by Maron if he could envision a future project that would bring them together, Letterman didn’t think so. “No, not really,” he replied, adding, “We were friendly. I liked him.”

During the appearance, Letterman also shared his opinions on other comics, including the late Robin Williams.

“You know in the NFL there would be a quarterback who doesn’t stand in the pocket, and just throws passes… there’s a quarterback who will run sideline to sideline to the opposite end zone, and then throw an 80-yard touchdown pass, and everyone says, ‘Wow, that’s the future of being an NFL quarterback.’ We thought that about Robin,” he said.

“George [Miller] and I used to watch him work, and we just both thought together: ‘We’re screwed. I’ll just go back to Indiana. I can’t do that.'” he continued. “He was so effortlessly effective, the place would explode, and you couldn’t follow him. Could you get an audience to explode and blow the roof off the place?”

RELATED: Kanye West Opens Up To David Letterman About His ‘Sprained Brain’

You can hear the entire interview right here.

The second season of Netflix’s “My Next Guest Needs No Introduction With David Letterman” premieres on Friday, May 31.