There are several antonyms for the phrase "dropt ball." It could be the opposite of a mistake or failure, which would be a success or accomplishment. Alternatively, it could be the opposite of a missed opportunity, which would be a seized opportunity or a successful outcome. Another antonym could be a flawless performance, indicating an error-free and impeccably executed task. Finally, the opposite of a "dropt ball" could be a winning moment, signaling a victory or a successful outcome in a competition or game. Overall, there are many antonyms to the phrase "dropt ball," and their meanings depend on the context and situation in which they are used.