The phrase "get upper hand" refers to achieving a position of advantage or control in a situation. Its antonyms, on the other hand, would imply a loss of power or status. These could include phrases like "fall behind," "lose ground," "give in," "yield," or "surrender." When one loses the upper hand, they may find themselves at a disadvantage, without control or agency, or facing an unwanted outcome. Being aware of these antonyms can help individuals navigate confrontational or competitive situations with a clearer understanding of the potential consequences of their actions.