There are a few things worth considering...it may not be down to your warm up...

At different times in the day your blood sugar levels will differ, depending on what you have eaten. At the end of the day the chances are that you have been steadily putting calories in all day. First thing in the morning you are likely not to have eaten for 10 hours or so, then eaten and played.

The type of food you eat is also important, look at what you eat a couple of hours before a game and compare carbohydrates, proteins etc.

Fluid levels / hydration status can play a part, you again are less likely to be as hydrated first thing (may also have been out the night before...alcohol dehydrates the system).

In the morning you are likely not to have moved around as much and thus may need a longer warm up period.

Static stretches are not always the answer...biking is a good started, then often more activity, high knees, bum flicks, simulating hurdling type activities can be useful...followed by more specific drills.

Hope this helps a bit