As if five straight 16-hour days of nonstop live music wasn't enough for one festival, Prince took the South by Southwest Music Conference into overtime with his closing-night party Saturday.

The Minnesota rock boss performed six encores at his invite-only promotional performance for Samsung, whose mobile devices had their batteries tested like never before as the little energizer kept going and going till 3 a.m. Sunday at La Zona Rosa nightclub.

"We're gonna show you how we do it in Minneapolis," he warned at the start of the first encore.

Of course, the way Prince has often done shows in his hometown is by first making the audience wait for their musical pudding. He didn't go on until nearly 12:30 a.m., when doors opened at 9 p.m. and many attendees started lining up hours before that. At least they were treated to a rare performance by influential hip-hop quartet A Tribe Called Quest as an opening act. Samsung gave out wristbands for this wowza double-header concert to users of their $700 Galaxy mobile phones, who had to rack up points at 11 different vendor locations in Austin. The company certainly deserves points for staging what may be the most elaborate SXSW party after Kanye West's big bash in a vacant power plant in 2011.

Even though La Zona Rosa is a full-time, hi-fi music venue, Prince still made Samsung build him a new stage from scratch along the long wall of the club to accommodate the 18-piece New Power Generation band lineup he brought with him. Throw in a stretched-out video screen behind said stage -- plus confetti guns and a bevy of glitzy lighting -- and the giant South Korean electronics maker had clearly spent a small fortune even before it handed over Prince's paycheck (which was undoubtedly a not-so-small fortune; at least $1 million seems like a good guess).

Even with all that visual eye candy – including the several different blouses Prince changed in and out of – the show's handlers still threatened to eject attendees for taking pictures with their mobile devices during his set. So yes: Prince demanded that nobody use the product he was there to promote.

The concert followed a similar pattern as last fall's Welcome 2 Chicago shows and his second night of January's three-night stand at the Dakota in Minneapolis. He only sang a few of the hits, starting with "1999" for the second song and "Purple Rain" just before that first encore break, 50 minutes past go (for a few minutes, it looked like Samsung wasn't getting its money's worth).

For the rest of the show, Prince often acted more like a George Clinton-like cheerleader than the spine-tingling singer that he is, always urging various members of his band to take solos, especially drummer John Blackwell and saxophonist Marcus Anderson. Thanks to his own disinterest in playing a guitar – was he afraid the Austin humidity might warp the neck? – Donna Grantis of his new 3rd Eye Girl band got some extra spotlight time, too. Ironically, he addressed his surroundings mid-show from a six-string context: "Austin, Texas: Just like I pictured it," he said. "You've got a lotta guitar players up here, don't you?"

Prince's current NPG lineup is killer, no question, but the crowd obviously didn't come to find that out. Some of the workout jams included "Musicology," Curtis Mayfield's "We're a Winner," James Brown's "I Don't Want Nobody to Give Me Nothing" and parts of the Jackson family catalog – Michael's "Don't Stop Till You Get Enough," Janet's "What Have You Done for Me Lately?" He rewarded diehard fans in the crowd deeper into the encores with some of "Something in the Water Does Not Compute" as well as snippets of "Housequake" and the Time's "Cool." By then, those nutty fans included Questlove, who apparently ran over after his competing gig with Justin Timberlake at the MySpace party several blocks away.

Prince just kept coming back out. The 2½-hour set was the antithesis to the wham-bam performances that the thousands of other bands in town had to play in quick order during SXSW – bands that, by the way, were losing untold amounts of attention from media and music professionals while conference attendees waited on Prince. At least the presumptuous Purple One offered something in the way of a benediction to fittingly sum up Austin's holy week: "I love being a musician," he said. "It feels like a service."

Maybe SXSW organizers should try to book him as the keynote speaker next year. You can bet that won't go over the allotted time.

A Tribe Called Quest's 50-minute warm-up set was more like a typical SXSW set, in that the New Yorkers tore through their songs rapidly, starting with "Steve Biko (Stir It Up)" and including "Can I Kick It?," "Oh My God," "Bonita Applebum" and the finale "Award Tour." Though largely inactive of late, the guys still displayed an ageless chemistry. After the latter tune, the group's forever-charismatic lead MC, Q-Tip, stuck around to mop up – literally.

"Do you know what I'm doing?" he asked the crowd as he toweled off the stage. "I'm cleaning up for Prince. I would never do this for anybody else."

Q-Tip clearly wasn't the only one to make that statement on Saturday. Read our full festival coverage at www.startribune.com/sxsw.