Tony Mendez, Dave Letterman's long-time cue card guy, got fired this week when he assaulted the Emmy-nominated staff writer he had been arguing with.

Mendez—who is often featured on the show—told the Post he began arguing with staff writer Bill Scheft as the pair competed for Dave's affection.

"Bill was always undermining me — making himself out as Dave's No. 1," Mendez said. "Trying to pretend that I wasn't even in the room . . . little passive-aggressive things."

Things apparently got physical when Mendez saw Dave take Scheft's side:

On Wednesday, Oct. 8, the three were rehearsing in Letterman's backstage digs at the Ed Sullivan Theater when Mendez said he reacted to one of Scheft's interruptions, telling him, "I know what I'm doing. Get off my back."

But suddenly Letterman growled, "Tony, your sour disposition isn't helping," Mendez ­recalled.

" 'You're the one who has the sour disposition, mothf–ker,' '' Mendez snapped back.

...

Still, Mendez said he was hurt by the exchange with his idol and boss of 21 years.

"That night I wanted to tell Dave how much that hurt my feelings," Mendez said. "And then I realized that this is what Bill was doing. He was trying to create a wedge between us so Dave would think I was an a–hole."

Mendez said he stewed all night and the next morning, when he got to work, he was literally at Scheft's throat.

According to the Post, Mendez grabbed Scheft and threw him against a wall before a Thursday taping. He was kicked out of the Ed Sullivan theater that day and formally terminated last Monday.

A representative for Worldwide Pants told Deadline that the company won't comment on confidential personnel matters, but the Post says Letterman is still giving Mendez full salary and health benefits through the end of the season.

[image via AP]