President Trumpon Saturday mocked Oprah Winfrey at a campaign rally in Pennsylvania, saying that he hopes the billionaire declares her candidacy for president in 2020.

At a rally for Pennsylvania state Rep. Rick Saccone (R), who is running for Congress this year, the president said that a Democratic challenge against him would be a “painful” experience for Winfrey, who has publicly stated she has no plans to run.

“I would love Oprah to win. I would love to beat Oprah. I know her weakness,” Trump told the crowd. “Wouldn’t we love to run against Oprah. I would love it. I would love it. That would be a painful experience for her.”

Trump declined to say what Winfrey’s “weakness” was, only mentioning that he had made an appearance on one of her shows in the past.

“I know her very well. I was on her last show, or one of the last, the last week. She had Donald Trump, and Donald Trump’s family. My, my, my, we have come down a long way, haven’t we,” he said.

Trump reacted to speculation that Winfrey could run on social media in the past, attacking her after a “60 Minutes” appearance interviewing voters.

“Just watched a very insecure Oprah Winfrey, who at one point I knew very well, interview a panel of people on 60 Minutes,” Trump tweeted in February. “The questions were biased and slanted, the facts incorrect.”

“Hope Oprah runs so she can be exposed and defeated just like all of the others!” he continued.

A Rasmussen poll in January found that Winfrey, if she decided to run, currently leads the president by 10 points among likely voters.