New York ? In an understated farewell Tuesday to the ABC News broadcast he has anchored for more than 25 years, Ted Koppel asked “Nightline” viewers to give his successors a fair break.

“If you don’t,” he said, “I promise you the network will just put another comedy show in this time slot. Then you’ll be sorry.”

It was one last dig in retaliation for his show’s most harrowing episode, when ABC executives in 2002 secretly courted David Letterman to replace “Nightline.” Letterman decided to stay at CBS and the attempt blew up in management’s face.

“Nightline” will continue Monday with a revamped format and hosts Martin Bashir, Cynthia McFadden and Terry Moran.

Since March 1980, Koppel offered a serious alternative to late-night laughs as the only anchor “Nightline” has known.

For his finale, Koppel looked back at one of his favorite interviews: his 1995 conversation with terminally ill college professor Morrie Schwartz, which led to Mitch Albom’s best-selling book “Tuesdays With Morrie.”

Fortified by a double mocha, Koppel didn’t sit down to write his closing remarks until Tuesday afternoon. His final show was taped several days in advance except for the ending, taped Tuesday evening.

He told viewers that he often quizzed “Nightline” interns on whether they knew old network anchors like Eric Severeid, Howard K. Smith or Frank Reynolds. He’d get blank stares in response.

“Trust me,” he said. “The transition from one anchor to another is not that big a deal. Cronkite begat Rather, Chancellor begat Brokaw, Reynolds begat Jennings. And each of them did a pretty fair job in his own right.”

He more directly thanked viewers for their loyalty in an e-mail sent earlier in the day to “Nightline” fans.

“It’s been a joy and a privilege to occupy this chair for the past 26 years,” he wrote. “I understand how many people grit their teeth on the way to work every morning. To have had more than 42 years now of almost always being able to go to work with a sense of excitement and anticipation makes me among the most fortunate of people.”

“Nightline” officially began in March 1980. After Koppel, a veteran ABC diplomatic correspondent, spent several months briefing viewers each night about the Iranian hostage crisis, ABC put him in that time slot permanently.