Boston got a nice dose of southern hospitality Saturday night at the House of Blues: Shovels & Rope, from Charleston, South Carolina, opened for Jason Isbell and The 400 Unit, from Muscle Shoals, Alabama, “for the most part.” Although both Isbell and Shovels & Rope fit into the big Americana tent that has gained so much momentum over the past few years, they are pretty different live acts. They complement each other well, though, and the crowd was clearly made up of people who know these artists well–there were just as many people who knew every word of the Shovels & Rope tunes as the Isbell ones.

Cary Ann and Michael (that’s Shovels & Rope) played a full-throttle set. They opened with “Swimmin’ Time” and “Gasoline” with Michael on drums, keyboards and harmonica and Cary Ann on vocals guitar. They let loose on “Coping Mechanism,” one of the best tunes on their most recent album: it shows off Cary Ann’s incredible vocals and their ability to push rhythm to the forefront of the live experience. They switched roles, with Cary Ann taking over drums, for “Bridge on Fire,” and “Cavalier.” In “Cavalier,” they slowed the beat way down and shared one microphone, which the most intense part of the set.

After their now-classic tunes “O Be Joyful,” and “Birmingham,” from their breakout album O Be Joyful, they rolled out a new song that they haven’t recorded yet. It was subdued, with Michael on guitar, no drums, the two of them singing into one microphone. The song was terrific and makes me excited about the possibility of a new album this year. There was part of me that wanted them to stay in that arrangement for a few more songs, to maybe do some of their other softer numbers (Lay Low or After the Storm) but they wrapped their 45-minute set with “Hail Hail.” They were less conversational than I’ve seen them in the past, but that is probably because they were trying to get as many songs into the opening slot as possible.

Isbell, coming off two Grammy wins a couple of weeks ago, put on one of the best shows I’ve seen in the past few years. He and the 400 Unit were able to operate up and down the register of intensity and subtlety representative of Isbell’s remarkable catalogue. They started with “Palmetto Rose,” from Something More Than Free, which includes a powerful hook that captured the audience from the get go. He followed with “24 Frames,” the Grammy winning Best American Roots song this year and two songs from 2013’s Southeastern, “Stockholm” and “Flying Over Water.”

We were lucky to have Amanda Shires in the band tonight. As Jason said, “she’s got her own band and her own shit to do,” so she isn’t always on tour with the 400 Unit. When the set shifted to some slower, less anthemic songs, her work on the fiddle elevated each and every one, beginning with “Dress Blues.” The song was written for Marine Corporal Matthew Conley and includes this powerful refrain: “Nobody here could forget you/ You showed us what we had to lose/ You never planned on those bombs in the sand/ Or sleeping in your dress blues.” Isbell, as I’m sure many of you know, used to be in Drive-By Truckers, and he played two songs from his time with them, beginning with “Decoration Day,” which provided space for soaring guitar solos from both Isbell and Sadler Vaden.

Unlike many band’s approach to setlists, there was not a pocket of softer songs isolated in the middle of the set. Rather, Isbell really effectively juxtaposed some of the quietest moments of the evening with the loudest. “Flagship,” which might be my favorite song from Something More Than Free followed the blistering solos from “Decoration Day.” Isbell only plays “Flagship” when Shires is there to sing and play with him and they exchanged knowing smiles with each other during this song about relationships, how they change and evolve (and sometimes devolve).

Jason mentioned that Garth Brooks was playing in Worcester and that he had to wait until they came on stage to tell Amanda so she wouldn’t skip their show to go see Garth. “I oughta get you a headset mic,” he said to Amanda. Amanda responded with the beginning fiddle licks to “Calling Baton Rouge.” It was a great running joke for the rest of the show, complete with Garth-like screams of “Yow!” and “Whooo!” Even though they were having a little fun, Jason said he saw Garth put on an incredible show at a state fair for one dollar just before “Friends in Low Places” came out. And while so many people want Isbell and Sturgill Simpson and Chris Stapleton to bash popular country, they seem to refuse to do so, knowing they won’t make their music better by talking about how bad someone else’s music is.

“Cover Me Up” was the most powerful song of the night for me. It followed the ironic Drive-By Truckers song “Never Gonna Change.” Isbell talked about how scary it had been to share this song with Amanda because “she don’t tolerate shitty songs.” Well. Good thing it’s one of the best songs of the last 5-10 years and the performance on Saturday was nothing short of spectacular. There just aren’t that many folks who have the vocal power and range to deliver a song like “Cover Me Up,” and also the restraint to hit the right emotional notes. The crowd roared at the line, “I swore off that stuff forever this time.” Isbell recently celebrated four years of sobriety, in large part due to Amanda’s holding him to his promise to get help. Isbell’s example is one that could really challenge the pernicious narrative that you have to get high to be creative. He addressed this in a tweet a couple of years ago, writing: “‘Substances make you more creative’ is a harmful myth junkies told/tell themselves so they can keep using. That’s all it is.” The last few songs of the set underscored and reflect on the choices and costs in life: “If it Takes a Lifetime,” “Super 8,” and “Children of Children.” After a break, he performed “Speedtrap Town” and “Codeine” for an encore.

“Wish we could have played longer,” Jason said at the end of the show. This is one of the challenges to playing The House of Blues–the show has to be done by 10:00 so they can turn it over as a nightclub. While I would have gladly stayed to hear more, they put together a beautiful show that was far more than a masterfully varied pace–the songs were put in conversation with each other throughout the night, reflecting the growth and depth of this artist who is only getting better.

Shovels and Rope said they’ll be back in Boston in the fall, which will be great, and Jason Isbell can’t come back soon enough. I’d go again tomorrow if I could.