There's no way of stopping dawn phenomenon (that I know of), but theknowledge that it occurs is all you really need. I've simply started taking insulin to combat it; I inject a dose specifically to counteract the rise that I know will happen. You might try this; or you might be better off simlpy making sure you always eat breakfast, and inject the appropriate amount to cover that (assuming that you can control your blood when you eat breakfast).
The exercise thing might be harder in your case. Generally speaking, very intense exercise can raise BG (due to a release of various hormones - think stuff like sprint intervals, heavy weight lifting etc.) and it can be necessary to inject insulin to cover the exercise. Longer, less intense exercise tends to lower BG (think cycling, distance running) and it can be necessary to lower insulin doses and / or eat carbs to cover this. Football is a mix of the two, and depending on how you're playing you might put in loads of short sprints one week then plod round a bit more the next. This would lead to totally different behaviours.
There's no easy answer to this because of the variability, unless you can guarantee to play at the same intensity every week (which you probably can't). You don't want to inject insulin beforehand as it might lead to a hypo, so probably the best you can do is to make sure you start the game with a good level and test at half time and again afterwards. If your blood's risen in the first half you might consider a small injection; if it's dropped then obviously take on some carbs.
The other thing is to get your blood under control straight away afte the game. This may be one of those lifestyle choices that you have to make - you might never get perfect control around a game of football, but you might be willing to sacrifice a few hours of good bloods for the pleasure of playing. And if you can manage to improve your control at other times you might still end up with great HbA1C's.
Hope that helps
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