Spoletians crammed in to the Cistern Yard for a one-night show from Sarah Jarosz on Thursday night. Blame the big old trees for blocking the breeze or just the sheer size of the crowd, but the heat was borderline unbearable, and when the songstress took the stage wearing a sweater and knee-high boots, the temperature seemed to rise a few degrees more. We made bets on how long it would be before she shed the sweater, but she kept it on for the whole show.

After getting situated center stage with cellist Nathaniel Smith and violinist player Alex Hargreaves, the Texas native Jarosz ripped into the first song, “Follow Me Down” off of her new album, without even acknowledging the crowd. But honest to God, when those first few notes started soaring through the air, they brought along a cool breeze. It stopped a few seconds later, but it was enough to lift our spirits. From there, 20-year-old Jarosz and company played a mix of new and old songs as well as a few covers. Throughout the evening, the bluegrass wunderkind switched between playing the acoustic guitar, banjo, and large-scale mandolin throughout the evening.

Some highlights included “Come Around,” from Follow Me Down, a cover of Bob Dylan’s “Ring Them Bells,” and “Old Smitty,” an instrumental that showcased Smith’s talents — he played that cello with a look of such animated joy it was hard not to smile. Jarosz introduced “Broussard’s Lament” as something she wrote when she was 14, then wailed through a song about the tragic aftermath of Hurricane Katrina, noting government’s failure to help those in need. An older gentleman sitting in front of me repeatedly made wrist-cutting motions during the song and left in a huff after it ended. He must have been a Republican.

But the majority of the audience was quiet and respectful for most of the songs, probably due in part to the singer’s shy, unassuming nature. Well into her set, however, she playfully called us out. “Y’all can whoop and holler,” she said. “I know it’s on you.” She also shared that the three of them had been to Husk earlier in the evening and gorged on pork chops.

Several audience members whooped when Jarosz introduced the haunting “Annabelle Lee,” a song inspired by the Edgar Allan Poe poem that may have been inspired by a local legend. She then moved into the highlight of the night, a bluesy take on Tom Waits’ “Come on Up to the House” that had the whole audience singing along. For the encore, the trio played a high-energy instrumental before Hargreaves and Smith left and Jarosz went solo for the final “Little Song.” The lullaby-esque tune ended the night on a serene, sleepy note.

To be honest, Sarah Jarosz and her young counterparts didn’t really look the part of world-class Spoleto performers. Despite her years of playing the bluegrass circuit, she seemed a little uncomfortable on stage, and her outfit was more appropriate for a backyard get-together than a major festival concert. But as soon as they started playing and the first words left her lips, it was obvious why Spoleto chose this young performer for the program. Barely out of her teens, Jarosz is already an outstanding talent, and she has nowhere to go but up.