We played our hearts off

This was spoken by Pittsburgh Penguins hockey player Carl Hagelin after winning the Stanley Cup.  It is a congruent conflation of “played our butts off” and “played our hearts out”  (to an extreme degree or very hard).  Out and off are the culprits here.  Of course, maybe Carl is a bridge player.  A big thanks to Jake Holdcroft for hearing this one on a local sports program and passing it on!