The casket is pictured leaving the memorial service of U.S. Senator John McCain (R-AZ) at National Cathedral in Washington, U.S., September 1, 2018.

Meghan McCain's apparent criticism of President Donald Trump at the memorial service of her father, Arizona Sen. John McCain, was in line with the late senator's outspoken style, two of his former Senate colleagues and friends told CNN on Sunday.

In her emotional speech at Saturday's funeral service — which Trump was not invited to attend — the younger McCain took veiled swipes at the president, blasting him for "cheap rhetoric" on American greatness. She never mentioned the president by name.

"The America of John McCain has no need to be made great again because America was always great," she said, emphasizing her father's vision of how he saw the nation during his service and appropriating the president's "Make America Great Again" campaign slogan.

South Carolina Sen. Lindsey Graham and former Connecticut Sen. Joe Lieberman, two of the Arizona Republican's closest allies and friends in the Senate, defended her eulogy in a televised appearance.

"She is her father's daughter," Graham told CNN's "State of the Union" in a joint interview with Lieberman. "If you say something bad about her dad, you will know it, whether you're the janitor or the President of the United States. She is grieving for the father she adored. I think most Americans understand that."

Lieberman added that he was a "proud uncle" watching McCain's speech at the memorial service.

"She was direct ... the way John was," Lieberman said.

The senators' defense came after McCain posted a photo of them online, calling them her "uncles forever." Graham, Lieberman and McCain were often referred to as the "three amigos" during their time in the country's top lawmaking body.