Lots and lots of luck.

Immediately getting the ball to Tidus is good, and shoot with him as often as you can in the first half. Try to shoot before more than 1 of the Goers can block you (and break past that 1), because if you get a clear shot, Tidus has about a 50-50 chance of scoring. If you're lucky, you can get 2 or 3 goals in the first half (and if you time it right, you can score a goal near the end and it won't give the Goers time to take another shot afterward). Stopping the Goers is mostly luck though. The RNG needs to be friendly to you to stop their shots.

If you manage to get ahead, pass the ball to a defender and swim inside your own net. A glitch in enemy AI will make them ignore you if you do this right.