Wiktionary
snatch defeat from the jaws of victory
vb. (context idiomatic English) To suddenly lose a contest one seemed very likely to win, especially through mistakes or bad judgment.
Usage examples of "snatch defeat from the jaws of victory".
The Jays have been known to snatch defeat from the jaws of victory before.
Time and again, I had managed to snatch defeat from the jaws of victory, often by only a hair's breadth.
Anything was possible when it came to my unerring ability to snatch defeat from the jaws of victory.