The Goers aren't really that tough. I didn't beat them my first time through and didn't play Blitzball again until my second playthrough. Second time around I beat them. I had the Jecht shot but missed the one time I used it (I forget how). I just got the ball to someone with a good pass stat, got most of their team away from Tidus or Wakka, passed and shot. Then I just waited out the clock pretty much. Not too tough, but when you're trying to get the hang of the game at the same time it's a little tricky.