UFC 2009 Undisputed
30 Achievements
1,000
Red Belt
Reach level 50 or higher in a Xbox LIVE Ranked Match.
100
How to unlock the Red Belt achievement in UFC 2009 Undisputed - Definitive Guide
It's time consuming if you want to boost or if you want to do it legit. Their are a few methods of getting the achievement faster, however.
First you must remember that if you simply get the snot beat out of you, without much resistance on your part, your going to lose more fans and points then you would if you brawled it out and lost a close match. So if you don't really feel like playing a match, chances are it's a better decision to not play it.
If your going to boost, grab a friend on your list. Once he's ready, both go to Custom match and get the same settings down. Usually it will prompt one of you to host a match, once you create it tell him to begin the search for your match with the same settings. It's not a completely great boosting technique, considering people usually join and he usually joins someone else' match, but I got 20 matches in an hour and half.
Remember to use submission and defense to the best of your abilities. If your really having problems, back out of the lobby on good, high ranked players and try to play poorly experienced people. A trick that works well and is very lightly used is the hard kicks. Not only do they hurt the opponent, they are a long distance attack and keep their stamina down. Don't get into a slug feast, stay conservative and use your kicks and submission moves.