BTW what were your flash settings set to?
Why would this be any different than shooting football with a flash? There were dozens of "What settings?" posts last Fall, so you should have tons of stuff to look through.
I shoot night field sports at ISO800, f/2.8-f/4.0 and 1/250s, with the flash on ETTL-II, using the FEC to adjust exposure. Some shoot the flash on manual, and this works, too. I like to simplify things, though, and the 580EX and EXII actually do pretty well in ETTL-II mode.
For the thousandth (?) time, while you may not like the "look", you can get much higher effective shutter speeds, better color saturation and whiter whites (sounds like laundry detergent) and reduce the impact of light-cycling using flash. When done correctly, you will minimize the flash look and reduce red-eye. And, unless you fire the flash from 5 feet away, on high power, with a player looking directly at you, the flash will probably not even be noticed. You will be the most if not the only self-conscious person on the field regarding the flash.
Based on shooting a few hundred night football games, I would never shoot night sports under ambient light if I had the chance to use flash. The only down side is the occasional red eye you'll get (especially with shots taken at a longer distance) but this is easily fixed in post processing.
And before anyone asks, no you shouldn't use High Speed Sync (HSS). Lotsa stuff has been written on this topic, too.