The phrase 'gotten the upper hand' embodies a sense of triumph, superiority, and dominance. However, there are many antonyms that convey the opposite or contrasting sensations. Some antonyms for this phrase could include 'fall behind,' 'lose ground,' 'yield control,' 'surrender,' 'submit,' 'capitulate,' 'concede defeat,' or 'give up the fight.' Each of these antonyms indicates a lack of power or authority, conveying a sense of defeat or loss. While the phrase 'gotten the upper hand' is often seen as positive, its antonyms can highlight the negative implications of a display of dominant behavior.