From the Main Menu Select:
- Custom Multiplayer
- Halo 2
- Halo 2: Anniversary
Map: Bloodline (variant doesn't matter)
The match will load and during the countdown, hit
and select "end game" as soon as you can.
When you get back to the lobby menu,
over to START and start another match. Just rinse and repeat the above steps to get your 10 matches.
Each iteration counts towards the following chievos...
and all of the other Win X Multiplayer achievments. It's a grind.
If you leave a negative vote, please leave a comment so I can improve the solution.