The phrase "embarrassing loss" refers to a situation where someone or a team is defeated in a way that causes them to feel ashamed or humiliated. Full definition
She also faced the music instead of going into hiding after an incredibly embarrassing loss. (sbnation.com)
Perhaps politicians who are good at gaining overwhelming trust in their local communities are also good at gaining support to become party leader; or (rather opposite / cynical) parties parachute their up - and - coming career politicians into safe seats so they reduce the risk of embarrassing losses. (politics.stackexchange.com)
Despite the fact that it was only put together in 2016, several members of the opposition party have blamed breaches in the biometric register for the party's embarrassing loss in last year's polls. (citifmonline.com)