Before 10 p.m. Friday, the High Noon Saloon sold out tickets to P.O.S. and was turning away people at the door. One young woman, refusing to accept her fate as one of the unfortunate outcasts, stood forlornly just inside the door, glaring and tapping at her cell phone between wails of frustration.

By the end of the night, the crowd had swelled to sardine-packed tightness up against the stage. It was "easily the most people that have ever come to a P.O.S. show," the rapper later told the crowd. "Easy."

That must, in part, have something to do with his final opening act, Dessa, a rising star in the same Doomtree Collective he co-founded in Minneapolis. Her warm delivery, her impeccable timing and insightful lyrics put her in the same league as P.O.S., if not soon to surpass him.

Both she and her producer, DJ Plain Ole Bill, were suffering head colds. It didn't slow them down. She took a swift puff on an inhaler between "Dutch" and "Matches to Paper Dolls," off her new album "A Badly Broken Code," but the congestion didn't affect her voice. Plain Ole Bill looked peaked. His coughing got so bad the night before that he vomited before going onstage, Dessa said, and now he was running on "iced coffee, hope and Dayquil."

Sickness also didn't slacken the duo's performance, which popped with elasticity. It began with how grounded Dessa is. Like a ballet dancer spinning a pirouette, she kept her focus forward and pulsing with intensity, tossing off words to the side in precise timing with Plain Ole Bill before snapping her voice and face back to the front. Snatches of her lyrics stuck long after she said them, like the line "I fixed you up when you were still a common sparrow" in "Seamstress," which crawled with repulsion and desperation.

Seattle rapper Astronautalis also made a good showing as opener. Then again, "good" is too plain and clean a word for this scramble of sinew and bug-eyed growl. His style is discombobulating at first -- part metalhead scream, comic impishness and a freakishly well-enunciated hip-hop flow.

Astronautalis powerfully held the audience's attention with only a mic and a laptop. He joked that his "crew" loaded in the mountain of gear and turntables behind him (really P.O.S.'s and Dessa's gear) solely to make him look tough and famous. In fact, they were so decadently superfluous that they were filled with chocolate.

"If you just peel off the silver, it's a Cadbury Creme Egg inside," he cracked.

Before finishing with "Trouble Hunters," off his 2008 album "Pomegranate," he treated the audience to an astounding freestyle over a Pharcyde beat using topic suggestions from the audience, including Vincent (the dog from "Lost"), a wolf with lasers in its eyes, an empty bottle, and "purple monkey dishwasher" (a nonsense phrase popularized by "The Simpsons").

By the time P.O.S. leapt onstage after midnight, the crowd had been whipped into a sweaty frenzy. With DJ Plain Ole Bill behind him, P.O.S. commanded a set of songs that bitterly deconstructed apathy ("We throw our hands up like we don't care anymore") and punched up an instigative message of "Carpe Diem" with fresh, cynically reversed language ("Every never is now").

He held court for at least an hour, jumping from song to song without much commentary, outside of a few thumb war challenges and exhortations that the crowd "get some spirit fingers up in here" (it obliged, but they didn't need much encouragement in the first place). He brought Dessa and Astronautalis onstage separately, too, for a few on-target collaborations. He and Astronautalis are working on an album together, P.O.S. said, that sounds like a mix of "rapping and Fugazi and maybe some real quiet Modest Mouse."

P.O.S., like Dessa, made the music and the lyrics clutch at the audience with urgency, hard-won wisdom and heart. It's the kind of show that leaves a lingering feeling of purposeful energy.

Next time they come, buy a ticket well in advance.