Idiom meaning rescued from a difficult or embarrassing…

Idiom meaning rescued from a difficult or embarrassing situation by a last-moment interruption. It comes from boxing, where a fighter knocked down near the end of a round could once be spared from defeat if the gong marking its end sounded before the referee finished counting to ten. A popular but unproven legend links it to coffins fitted with ringing devices. It also became the title of a teen sitcom.

The answer in 14 letters