When a person fails to achieve in a sporting event that they have dominated.
When a person loses a sporting event based upon they're own mistakes.
Person 1: I've got this in the bag! No chance anyone can beat me.
*Person fails to win*
Group: He Ambrosed It!
Person 1 is dominating a race, person one crashes on last lap of race to lose. The said person has, "Ambrosed It"