A nice little piece of thinking here that Everyball coach Seb Calcutt picked up on his LTA level 4 Senior Performance Coach course recently:
If you're determined to win you'll think logically on outcomes to achieve victory with effective use of physical output.
If your desperate to win you'll think illogically (and possibly irrationally) over issues out of your control like wind, bad bounces etc with non-effective use of physical output.
You'll often see that in a contest. One player/team determined, the other desperate.