In sports, a "Hail Mary" play refers to one that is risky, daring, and unlikely to succeed, but is also the athlete or team's only hope of pulling off an improbable last minute victory. It's thrilling when it succeeds because the chances of success are quite low, and the stakes are so high. Hail Mary plays are essentially desperation plays, and successful ones have made for some of the most exciting moments in sports.
On the contrary, the "choke job" refers to when a favored athlete or team is believed to have an easy victory at hand, but somehow improbably has a lapse that costs the athlete or team the victory to a much inferior (at least on paper) opponent. These make for the biggest upsets or disappointments in sports.
So what are the great Hail Mary plays and choke jobs of wuxia fiction?