PHOENIX — Rihanna paused between "We Found Love" and "Love the Way You Lie" to check on Super Bowl revelers, some of whom were running on fumes after a week full of parties, concerts and drinking.  "Arizona, you're not tired yet, are we?"  Her playful concern was met with screams that only grew floor-tremblingly louder, five songs later, when she brought out Kanye West as an unscheduled guest, turning Saturday night's lineup into one that may rival even Katy Perry's halftime show.  Rihanna, already 15 songs deep into her DirecTV-sponsored set across the street from the game-day stadium, stayed with West for "All of the Lights" and "Run This Town." West surprisingly flew into solo mode for nine more songs, with VIP audience members like John Legend and Aaron Paul nodding their heads in rhythmic approval.  Awakened by West's pulsating beats and crisp lyrical flow, fans got lost in everything from party anthem "Gold Digger" to "Only One," the emotional sendup to his mom.  A sweaty West capped his appearance by transitioning Rihanna into the show's closer, "Diamonds." That's where it ended, with no encore, and without the pair performing their new Paul McCartney-assisted "FourFiveSeconds" track. Still, the crowd seemed to leave satisfied.  McCartney and Jay Z were rumored to appear, but didn't show up. Had those rumors come to fruition, they would have further established music's important role in Super Bowl festivities, as the largest parties here relied on big-name musicians — instead of athletes — to attract hordes of revelers.  Aside from Perry's halftime show and the actual Super Bowl game between the Seattle Seahawks and New England Patriots, Rihanna's invite-only party was the hottest ticket in town, with executives and socialites jostling to get on the relatively intimate guest list.  Rihanna treated them to a polished set, performing her expected dance hits, including "We Found Love," "Live Your Life" and "Where Have You Been."  But the 26-year-old superstar, who is expected to make a major comeback in 2015 with her first studio album since 2012, was at her best when she powered through a medley of ballads, ranging from "Love the Way You Lie" and "Cold Case Love," to "Hate That I Love You" and "Stay."  Rihanna's private pre-Super Bowl party capped off a week of StubHub-ticketed concerts across from the University of Phoenix Stadium, where the NFL champions will be crowned Sunday night to much fanfare. Zac Brown Band launched things on Wednesday, Calvin Harris kept the party going on Thursday, and Imagine Dragons and Snoop Dogg lit up the stage on Friday.  Rihanna, who will likely be in the stadium to watch friend Perry entertain more than 100 million television viewers, might keep her musical momentum going by surprising the world onstage during the halftime show as another one of Perry's surprise guests.  If not, there's always hope she'll headline next year, especially since she's one of the top-selling female artists ever (only behind Madonna, Mariah Carey, Celine Dion and Whitney Houston).  Rihanna = future Super Bowl halftime show performer. Please, NFL gods? Her pre-#SB49 concert was stunning last night. pic.twitter.com/TkQmebyuf1  — Brian A. Hernandez (@BAHjournalist) February 1, 2015
Rihanna surprised guests at her invite-only Super Bowl party concert by bringing out Kanye West for a dozen songs. Rihanna and Kanye for 2016 halftime show?