Donald Trump and Hillary Clinton participate in their first presidential debate, at Hofstra University in Hempstead, New York, on Sept. 26. (Rick Wilking/Reuters)

Post-debate, plenty of pundits and armchair analysts pointed to Donald Trump’s remarks about comedian Rosie O’Donnell as a moment when the GOP presidential candidate had gone off the rails.

Prodded by Democratic rival Hillary Clinton about his comments about women — “This is a man who has called women pigs, slobs and dogs” — Trump name-checked O’Donnell, with whom he has had a long-running feud.

“Somebody who’s been very vicious to me, Rosie O’Donnell, I said very tough things to her and I think everyone would agree that she deserves it and nobody feels sorry for her,” Trump said.

Why bring up O’Donnell, whom Trump has called a “loser” and “fat”?

Seems it’s a talking point for Trump — hey, all politicians have them. It wasn’t the first time he has invoked O’Donnell’s name at a similar forum: During a Republican primary debate, Trump faced a similar question, this time from moderator Megyn Kelly of Fox News channel: What’s the deal with calling women “fat pigs,” “dogs,” “slobs” and “disgusting animals”?

His reply then: “Only Rosie O’Donnell.”

Trump was pleased with his answer, boasting the following day about it during an appearance on “Fox and Friends.” ” I came up with the Rosie O’Donnell statement, which really got a tremendous applause,” he said. “That was the biggest applause in the evening, actually, so it was sort of interesting.”

So although the talking heads parsing Monday night’s debate may have questioned the wisdom of using precious lectern time on subject matter that gets the GOP candidate in trouble with the female voters he needs to attract, Trump seemingly knew what he was doing — using a go-to line that he liked (and liked the reaction to) from a previous debate.

O’Donnell responded by tweeting a video of the initial comments she made about Trump in 2006 when she was a co-host of “The View” that seemed to spark the real estate mogul’s long-standing animus. She called it “the 5 mins orange [body part of the nether regions] can’t seem to get over.”  She urged followers to “tell the truth – shame the donald.”

And her pal and “A League of Their Own” co-star Madonna threw her support behind O’Donnell. “Mess with my girl Rosie and you’re messing with me!!!” the pop star tweeted. “Cruelty never made anyone a winner.”