Led Zepplin's debut(in the States) blew away Spirit(I think it was the Filmore West.). Lonnie Mack blew away Edgar Winter at the Filmore West. Grateful Dead blew away the Band-New Year's Eve at the Civic Auditorium in S.F.
'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.