NBA 2K9

If you want to do this legit, good luck because this is a very tough achievement to get now because the only people that play this game still are amazing. What you have to do is win 5 ranked matches in a row, obviously, but you MUST win the 5th game straight up. If the opponent quits in the 5th game, you won't get the achievement. This can be really tough because if your beating someone, they usually either quit out or just sign out so you don't even get the win. I had that problem a lot as I would go on 5 game winning streaks and they wouldn't count because that 5th game the opponent quit early. And then I lost one and got pissed. What i did is just boosted for it because I couldn't stand it anymore. Hook up with a friend or just find someone with this game and go to ranked custom match and choose street game. You can have your friend quit out for the first 4 times and then have him let you beat him for the 5th. Note: score goes up to 21pts in street game and you will not see who you are playing until you pick your two players (party chat is recommended so you can pick a certain player every time to know that your playing each other). If you have any questions or need a person to do this with hit me up i'll be happy to help you get this tough achievement.

Win five online games without losing a single match.
If you are having trouble with defense or offense, try the tutorial and Season training sessions. They actually teach a lot of stuff.
And when you are practicing or playing against a friend, Play on Hall of Fame to better yourself against your opponent.

Good luck and I'll see you on the court!