It's been a surefire recipe for a summer jam since 2003: Take a snippet of a '70s soul corker, twist it until it loops around on itself, then heat up the concoction with a spitfire vocal performance. (See also: "Crazy in Love," "1 Thing.") Hip-hop mastermind DJ Premier uses that plot to terrific effect on Christina Aguilera's new single, which leaked last week—"Ain't No Other Man" is so urgently amped, it makes poor Beyonce and Amerie seem like shy types who spend the hottest days of the year doing crosswords at the kitchen table. Aguilera, whose insistent pipes have added ferocity to even her most burbly material, owns "Ain't" from tip to toe. And when she rhymes "all my friends" with "past and present tense" (!), the song gets pushed from a car-radio banger to a force that yanks every hip within a 50-mile radius into a frenzied wiggle.