Not a lot of bands go from playing the cramped 7th Street Entry straight to the cavernous Roy Wilkins Auditorium, but the Postal Service made that remarkable leap Friday. Never mind the fact that the electro-pop duo went 10 years between local gigs.

A side project of Death Cab for Cutie frontman Ben Gibbard’s, the duo issued its one and only album, “Give Up,” and went on a short tour in 2003. Gibbard’s full-time group then broke big, and that was that. Or so it seemed.

Friday’s sold-out, heavily-under-30 fans — including many who weren’t even yet teenagers in 2003 — acted like they were seeing a favorite dream come to life. In the interim decade, the Postal Service has produced countless sound-alike acts (Minnesota’s Owl City being one) and grew into a staple of dorm-room, coming-of-age mope sessions. A two-CD reissue of “Give Up” in April prompted Gibbard to finally reunite with his PS mate, electronic producer Jimmy Tamborello.

“It just goes to show: If you want your band to be successful, just play 7th Street Entry and wait 10 years,” joked Gibbard, who was uncharacteristically all smiles all night.

But then what red-blooded male wouldn’t be cheery when Jenny Lewis is beside him all night? The Rilo Kiley frontwoman, who sang on “Get Up,” added oodles of playfulness to the 80-minute set. She danced like a teenage clubber with Gibbard in “Nothing Better” (in which she also sang lead vocals) and traded off drum duties with him from time to time. Laura Burhenn of Omaha’s Mynabirds also joined in on keyboards and harmonies.

Aside from adding life to the party, though, the extra vocalists weren’t really needed, what with the way the audience loudly sang along to such songs as “We Will Become Silhouettes” (second on the set list) and “Such Great Heights” (pre-encore finale).

It really was a surprise how well the music held up — not just in the 10-year interim, but in the transformation from intimate, homemade, laptop-produced tracks to tunes well-suited for a large, high-energy concert. Among the most unforeseeable highlights, “Be Still My Heart” proved far more climactic and nervy on stage, and the reissue bonus track “Turn Around” became a sassy romp.

Some of it proved to be filler, too. The bonus B-side “There’s Never Enough Time” never fully gelled, and even the album track “Recycled Air” lagged. On the other hand, Gibbard & Co. added two fun extracurricular cuts: “The Dream of Evan and Chan” by Tamborello’s main act Dntel and “Our Secret” from the Beat Happening — whom Gibbard introduced as “the greatest band west of the Replacements.”

Adding greatly to the concert’s sweet tone was opening act Mates of State, aka Midwest-reared couple Kori Gardner and Jason Hammel. The piano-pop spouses played as a duo but went over big with “Get Better” and a finale cover of Daniel Johnston’s “True Love Will Find You in the End.” The latter could’ve been the theme song for Friday’s long-awaited love-in of a concert.