From The Jargon File (version 4.4.7, 29 Dec 2003):
win
[MIT; now common everywhere]
1. vi. To succeed. A program wins if no unexpected conditions arise, or
(especially) if it is sufficiently robust to take exceptions in stride.
2. n. Success, or a specific instance thereof. A pleasing outcome. “So it
turned out I could use a lexer generator instead of hand-coding my own
pattern recognizer. What a win!” Emphatic forms: moby win, super win,
hyper-win (often used interjectively as a reply). For some reason suitable
win is also common at MIT, usually in reference to a satisfactory solution
to a problem. Oppose lose; see also big win, which isn't quite just an
intensification of win.