Bottle job

Failure to clinch a success from a position of significant advantage either from perceived strength or the status of the competition, such as going up 3-0 in a best of 7 series only to get reverse swept and lose 4-3. While not confirmed, it may come from the idea of having it "in the bottle and failing to put the cap on it" letting it escape.

The 19-0 Patriots going into the Superbowl losing to an Average-at-best Giants team to go 19-1? One of the biggest bottle jobs in history.