One-downmanship context and source: 'White Sox fans have suffered longer than Red Sox fans without winning a world series. But Red Sox fans -- who think of themselves aggrandizingly as a Nation, not a family -- have suffered more grotesquely. This is a critical distinction in their game of one-downsmanship.'
apparent meaning: To try to outdo someone else in a negative way
dictionary entry: One-downsmanship – n. the practice of out-doing another in a more negative manner or performing less well than another.