There are ethics and then there are aesthetics. In the world of popular music, both often get trumped by money.

Take the case of Steely Dan, the Rock Hall of Fame duo known for the quirky hits "Rikki Don't Lose That Number" and "Black Cow." Last September, cofounder/guitarist Walter Becker died, but cofounder/keyboardist Donald Fagen, the lead singer, has continued to tour with a cast of studio musicians, resulting in lawsuits between Becker's estate and Fagen.

Fagen didn't exactly sound gracious Friday night at Xcel Energy Center. "I wish my partner could have been here tonight," he said early in the evening. "He's not going to be here. He's just not. We sure miss him."

Fagen never mentioned Becker by name or dedicated a song to him or explained that the unused microphone stand in center stage was for Becker.

Truth be told, Becker was not essential aesthetically to Steely Dan's live performances. However, he was crucial in the studio, where this reclusive duo lived. But ethically speaking, he was missed on Friday.

Fagen, 70, who met Becker at New York's Bard College, is a cynical and sardonic guy. He kept referring to Steely Dan's oldies being from the Jurassic era.

Lead singer and keyboardist Donald Fagen of Steely Dan performed Friday night at Xcel Energy Center in St. Paul.

"No one likes jazz, do they?" he asked at one point. When a smattering of the nearly 8,000 fans responded, he seemed momentarily pleased. Then he introduced his three female backup singers as "the Dan-ettes" and let them sing "Dirty Work," the recording of which had featured Steely Dan's original lead singer David Palmer.

Yes, jazz has always been a principal component of Steely Dan. Nerds preoccupied with hip notions from the jazz and beatnik worlds, Fagen and Becker became America's biggest un-rock 'n' roll rock band in the 1970s with their sophisticated mix of jazz chordings, rock dynamics, brassy funk, pop vocals and warped, irony-laced lyrics.

Although Steely Dan hardly has a made-for-an-arena sound, Fagen and his eight instrumentalists and three singers impressed on Friday. Guitarist Jon Herington was the MVP with his various fills and solos in a wide range of flavors. The four horn players were outstanding, and drummer Keith Carlock was a consistent force holding it all together.

In short, Steely Dan sounded better than ever live.

The FM radio classics "My Old School," a funky "Black Friday" and the popish "Reelin' in the Years" were clearly big crowd favorites, but Fagen's solo hit "New Frontier" also was a winner. In the end, he did honorable duty, not dirty work.

If Steely Dan was 1970s music for foodies, then opening act Doobie Brothers was meat and potatoes, playing a good-time bar band mix of rock, blues and gospel. Like Steely Dan, the Doobies have undergone numerous personnel changes over the years. Singer/guitarists Tom Johnston and Patrick Simmons are still on board, and their band, buoyed by Little Feat keyboardist Billy Payne, sounded tight but still stretched out on guitar, keyboard and saxophone solos.

A highlight was "Long Train Runnin'," during which Johnston got fired up. And the crowd-pleasing Doobies got fans to sing along to "China Grove" and "Black Water" with the "Minnesota moon" shining.

Other than the fact that Michael McDonald was a member of both Steely Dan and the Doobie Brothers, they also share a manager, industry powerhouse Irving Azoff. It's surprising that he'd let them go on tour with such a no-frills production, with a light show worthy of a church basement.

Twitter: @JonBream • 612-673-1719