doesn't quite fit but there where times at winterland when the Dead and the Jefferson Airplane would play with maybe a band inbetween their sets. It started at about 7 or 8 and ended around 2 a.m. or so. Totally indifferent as to who blew who away they both did it to me
'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.