“We either did something really right, or really wrong,” Ken Stringfellow deadpanned as the giant stained-glass panels on both sides of the Central Presbyterian Church stage suddenly beamed with glowing light near the end of Friday’s performance by Big Star’s Third. We’re going to go with the former.

More than a dozen musicians played nearly two dozen songs associated with the legendary 1970s Memphis rock/pop band Big Star, focusing on their cult-favorite “Third” album but stretching out to include other favorites as well. Timed to coincide with the premiere of the concert film “Thank You Friends: Big Star’s Third Live … and More” at South By Southwest, the show was less of a special-guest affair than the movie (which included Wilco’s Jeff Tweedy, Semisonic’s Dan Wilson and others), but was no less musically inspiring.

That was thanks largely to Austin’s own Tosca Strings. Their classical-tinged introductions to several songs, along with gorgeous supporting passages throughout the show, perfectly fit Central Presbyterian’s stately environs. A small handful of electric rockers didn’t fare as well, echoing around the church’s towering ceilings. But when everything clicked, the music was as beautiful as anything heard at SXSW this year.

R.E.M. bassist Mike Mills, who’s been involved in this collective since the beginning, gave the night some star power, singing a couple of numbers at the start and end of the show while frequently playing bass on other material. But it was the show’s hushed middle section that was most moving. Core members Skylar Gudasz and Brett Harris (who also played flute and guitar/mandolin, respectively) stood out on “Thirteen” and “Kangaroo.” Band leader Chris Stamey took a lead vocal on the mesmerizing “Holocaust,” with a midsection that brilliantly fused the beauty of the Tosca Strings with distorted guitar swirls from Stamey and fellow North Carolinian Mitch Easter.

Big Star co-founder Jody Stephens and Big Star’s Third tribute band leader Chris Stamey at Central Presbyterian Church for SXSW on Friday, March 17, 2017. JAY JANNER / AMERICAN-STATESMAN

Drummer Jody Stephens, the sole surviving member of the original Big Star band, stepped out for lead vocals on several tunes and offered up sincere thanks to all involved at the end of the night. And Stringfellow, who seemed all over the stage throughout the night helping to keep the circus-like ensemble organized, offered a poignant reminder in the encore: “Seven years ago tonight, the world lost a fantastic musician, Mr. Alex Chilton.”

Big Star leader Chilton’s death on the eve of a 2010 SXSW performance sparked a spontaneous musical tribute show at the old Antone’s that partly created the template for this now-permanent (if ever-shifting) tribute ensemble. So, yes, without a doubt, the answer to Stringfellow’s question is that they did something really right.