Rosanne Cash (right) and John Leventhal

John Leventhal and Rosanne Cash 

Maybe the most underrated act in the music biz is the longtime romantic duo. They not only finish each other’s sentences, but their humor can be quick and spontaneous. They can get under each other’s skin but make up oh so quickly. They’re wed to each other but not to a set list. In other words, it feels real, not like a choreographed and practiced act. It’s not shtick.

Case in point was Rosanne Cash and John Leventhal Monday night at the sold-out Guthrie Theater. The way they interacted, the way the jabs and repartee kept coming, they could have been in the kitchen together trying to prepare a meal together with no one watching. But they were in front of an audience singing songs that they’ve written or recorded together.

Cash, the more famous half of the married couple of 25 years, writes the lyrics, Leventhal sometimes composes the music, produces the records and plays guitar, piano and other instruments. He’s collected five Grammys, she has earned four.

They would have merited another one Monday at the Guthrie if there were a Grammy for best duo performance by a romantic couple. It was the most delightfully memorable performance by a couple since the banjo duo of Bela Fleck and Abigail Washburn at the Guthrie in 2018.

On Monday, the music was enriching and profound, the vocals were passionate and moving, the guitar work was tasty and understated, the humor was witty and frequent, the vibe was the flawless balance of the graceful and the playful.

The humor never got in the way of the music. And once it actually made the performance unforgettable. Cash and Leventhal were doing Hank Snow’s “I’m Movin’ On,” a tune she said had been on the list of 100 essential country songs that her monumental father, Johnny Cash, gave her when she was 18. However, she waited until she was 54 before she recorded a bunch of those songs on an excellent album called “The List.”

As planned, Leventhal took an acoustic guitar solo in the middle of “I’m Movin’ On,” going from a little predictable twang to, surprisingly, a little Hendrix, and Cash thought it so amusingly unusual that she burst into repeating the refrain of Prince’s “Purple Rain.” A Hank, Hendrix and Prince mashup. Whoda planned it?

Afterward, Cash explained that one of the most psychedelic moments of her life was witnessing her dad singing “Purple Rain” at his Rock and Roll Hall of Fame induction when Prince was in the audience. Suddenly, Leventhal burst into an impression of deep-voiced Johnny Cash doing “Purple Rain.”

The entire Guthrie broke up – including the singer everyone paid to see.

“Was anyone illegally recording that?” a grinning Cash asked. “Cuz I would love a copy.”

There were plenty of serious moments, too, as Cash surveyed her 40-year recording career, with an emphasis on her two most recent albums, the triple Grammy winning “The River and the Thread” and 2018’s “She Remembers Everything.”

The singer often told the backstory of a tune, such as how a Shakespeare line sparked the title of “The Undiscovered Country,” which she said is about the space between people in a relationship. It was one of the night’s most powerful and eloquent performances.

The trigger behind “When the Master Calls the Roll” was that Cash had family members fighting for both the Union and the Confederacy in the Civil War.

In the middle of the 1¾-hour performance, the friendly Cash asked for requests but then had to reject most of them because she either couldn’t remember the song or was saving it for later (i.e. her 1979 classic “Seven Year Ache”).

She did essay one requested oldie, 1985’s “Pink Bedroom,” but managed to recall only two lines and couldn’t fake the rest.

At least, she could lean on Leventhal to help out on the Don Gibson classic “Sea of Heartbreak,” a duet she and Bruce Springsteen recorded for “The List.” It was one of many highlights, along with “Long Black Veil” with its haunting grace, “A Feather’s Not a Bird” with its swampy guitar, “Blue Moon with Heartache” with its wistful longing and “Ode to Billie Joe” with its down-tempo melancholy and Leventhal’s spooky guitar fade out.

He knows how to perfectly complement her singing, lyrics and humor. A match made in musical heaven.