A good joke takes time to set up. Comedians can’t just rush the punch line; they have to finesse it, tease it. For Flight of the Conchords, the New Zealand musical comedy duo turned HBO stars and, subsequently, best-selling recording artists, this means introducing their novelty songs with a bit of talk.

Generally, the low-energy, between-song chatter is the weakest part of the Conchords’ act, but at least it’s over with quickly enough—unless, that is, a loutish audience prolongs the formalities with incessant hollers and catcalls. For much of their sold-out show Sunday at the Riverside Theater, the Conchords were barraged by audience interruptions. They did their best to volley—Jermaine Clement, in his finest impromptu of the evening, likened one offender’s shrill voice to “that guy from the B-52’s,” breaking into a snide Fred Schneider impression—but the crowd only gave them so much to work with. There’s simply no funny way to respond to a witless boor screaming “MILWAUKEE!”

As the evening progressed, the duo became more explicit in their requests to leave the comedy to the people onstage, but the audience was resolute. “Damn it, we paid good money to see those guys from TV,” you could almost hear them thinking, “so now we’re going to bark indecipherable phrases at them mid-skit.”

The show’s pacing was inconsistent, but the songs—when the Conchords finally made it to the songs—were spot on. Stationed at a pair of high chairs with a few, mostly acoustic instruments, the duo didn’t have their program’s elaborate music-video accompaniments to fall back on, but their astute genre parodies came across even without the visuals. Although the crowd cheered loudest for familiar material from their TV show—the hot-buttered domestic sex jam “Business Time,” the radio-censored, Neptunes-styled rap “Mutha’uckas” and the David Bowie homage “Bowie,” perhaps the most incisive Bowie appropriation since Of Montreal’s last album—several new tracks stood out as well. One in particular, a droll duet between Clement and an imagined choir of 50 ex-girlfriends, was so realized that weaving an episode of their show around it should be a breeze.