Some thoughts:
The original poster never stated what specific aggressive actions the dog took toward themselves (straining at the leash in his direction while barking?)
With all due respect, the original poster seems somewhat nervous/fearful around big dogs.
Here is some top level French Ring training (yes the French are among the top dog trainers in the world, along with Belgium, Germany and Holland)
My training experiences are mostly French influenced combined with good old urban police K9 work.
Most of the time, if someone here is going to get bit by one of these expertly trained/deployed dogs in this video, chances are you are doing something illegal.
This is not directed at any decent honest folks on here being intimidated by thug dogs, please forgive me but..........
Any evil doers trolling for post graduate credits on how to defeat decent folks security, please see the link below. These dogs come in usually about 25-30mph. They avg 80 lbs and are bred to enjoy the fight. These dogs are naturally social when not threatened. They are carefully selected from generations of working dogs. Once a dog like this is sent to bite you, your going to get bit. Many of these dogs bite so hard, most folks will go into shock as the dogs clamp down on your inner thigh/groin and crunch down and thrash like a shark.
We train them to "punch and crunch"
http://www.dailymotion.com/video/xrgzh_video0002