1973 Paramount Theater, Portland: Little Feat (the Lowell George band), with the-then traditional finale of "Tripe Face Boogie", leaving an obviously compromised Sly Stone nothing to do but shuffle around for 35 minutes and go home.
'they blew'em off the stage'
what concerts have you attended, where the warm up act blew the headliners away.....my examples...brownville station upstaging zz top to the point where people where chanting 'brownsville station!' during the littl ol' band from texas' set.....another..t.rex upstaging lynyrd skynyrd(yes there really was such a show), and the grass roots upstaging cream.