This achievement is for completing the Homecourt Challenge mode of the game. You win the achievement once you win the tournament on "your Homecourt".
The remainder of this solution is my standard advice for this game mode:
Obviously, this is much easier on "Easy" difficulty.
Continuously play all of the challenge events, including the "Court Access" events. This will continually increase the level of competition, and will allow you to recruit new players and access gear. Gear will help you level up faster, improving your skills.
You start with some pretty weak teammates. Whenever you can recruit better players, do so. I generally played with a forward and a center as my teammates -- players with rebounding and dunking skills. I used Josh Childress with both created ballers -- he's fast enough to get down the court, rebounds well, dunks well, and shoots the 3 well (good for the shots-only events). I had a bona fide center as my other player, someone like Emeka Okafor or Drew Gooden.
For my created baller, I used a guard or forward. Once you reach Level 5, you can select a "freak" skill (a max stat skill) -- I strongly recommend selecting dunks. It will make it very easy to double dunk, and with your other players rebounding, you'll have a lot of outlet pass situations. Once I got my skill level up in the game (both my player and my gameplay skils), I was routinely winning matches with scores like 21-2 and 15-1.
For the second max stat skill (your "master" skill) I selected rebounding. This will allow you stop almost all shots the AI opponents take, unless it is a lay-up near the bucket.
Once you get comfortable playing the game, GameBreakers can be a great help, too. Nothing beats scoring 5 points on a triple dunk (and knocking one point off of their score as well).