The view from the Statesman Skyline Theater at the Long Center at the start of the Boston/Dennis DeYoung double bill on June 11, 2016. Photo by Scott Moore for American-Statesman

The music was a throwback to classic rock’s heyday, but the venue was brand new. Austin’s ever-changing skyline dominates the views from the new Statesman Skyline Theater, where Boston and Dennis DeYoung played the inaugural show at the converted front lawn of the Long Center.

A-LIST GALLERY: Photos from the Statesman Skyline Theater debut

A few thousand concertgoers funneled into the venue shortly before sundown, some arriving around 6 p.m. with a “picnic pass” that allowed them to bring in their own food. Others grabbed bites from a few food trucks on site, as the grounds gradually filled with blankets and folding chairs on the slope looking over the stage set in the northwest corner of the property.

There had been some concern about possible sound bleed into Palmer Events Center, where the Austin Symphony Orchestra was performing, but reports from inside the center indicated no issues arose. Parking was more complicated: Most of the Long Center’s garage spots went to Symphony attendees and VIP ticket holders, while others parked in nearby garages and lots (including the Statesman’s, about a half-mile away).

The opening act, taking the stage just before 7 p.m., was billed in full as “Dennis DeYoung and the Music of Styx” because other former members hold rights to the name. DeYoung and guitarist August Zadra handled vocals on a 40-minute set of tunes that featured the 1970s staples “Lady” and “Come Sail Away” as well as early ’80s “The Best of Times” and “Mr. Roboto.”

Between sets, some concertgoers took refuge in the Long Center’s air-conditioned lobby. As the sun set, the high-80s temperatures on the lawn began to subside, leading into a relatively mild twilight as Boston hit the stage just past 8 p.m.

The irony of this double bill was that the opener was a singer without his former band, while the headliner was a band without its former singer. Boston vocalist Brad Delp committed suicide in 2007; founding guitarist Tom Scholz, also the band’s primary songwriter and producer, found current singer Tommy DeCarlo via a cover song posted to MySpace. (DeCarlo was working at a Home Depot in Charlotte, N.C., at the time.)

Scholz is the only original member, though guitarist Gary Pihl has been with the band since 1985. Still, the seven-piece lineup re-created signature smashes such as “More Than a Feeling” and “Don’t Look Back” with near precision, and the quality of the sound at the new venue proved to be quite good for an outdoor setup.

The general-admission crowd was loose and laid-back enough to allow those who wished to venture down front for a few songs to do so easily. Sight lines from most of the front lawn were good, though views from the back lawn beyond a bisecting sidewalk mostly were obscured by those standing on an elevated sidewalk lip. That wasn’t much of an issue on this night, but it’s a potential problem with a full-capacity crowd.

After a finale that featured the instrumental “Foreplay” leading into the 1977 hit “Long Time,” the band returned for two quick encore tunes before wrapping up a few minutes before the 10 p.m. curfew. Four more concerts will follow at the venue this summer and early fall, with the Steve Miller Band performing on July 26, Culture Club on Aug. 2, the Goo Goo Dolls on Sept. 11, and Needtobreathe on Oct. 23.

Boston’s 40th Anniversary Tour at the Statesman Skyline Theater at the Long Center on June 11, 2016. Photo by Scott Moore for American-Statesman