Rockblock

The act of outperforming a musician or band unexpectedly when the musician or band was expected to be the better act.

The act of using a high level of talent unexpectedly and by contrast of talent level, disrespect a more amateur performer.

When an opening band performs at an amazing level, the headliner can get rockblocked.

Michael was playing a couple of tunes at a party when U2 showed up and played an impromptu gig. U2 are a bunch of rockblockers.