This phrase exaggerates victory to imply overwhelming superiority, not just a win. In the chess tournament, he completely blew his opponent out of the water.
Pro Tip 2/3
Unexpected Triumph
Use when a victory or performance is surprisingly much better than expected. She blew the top students out of the water with her perfect exam scores.
Pro Tip 3/3
Informal Context
It's casual, suitable for everyday conversation but not for formal writing. Our team blew the competition out of the water at the sales event!