Can be done easily by using a second controller in a local multiplayer match. Go to Gameplay Settings from the Main Menu and set MATCH TIME to OFF. You'll have as much time as you need this way.
Start a match and use your second controller to attack and damage the side where your main profile is signed in until you have very little health left. 10% may be hard to eyeball, so just get it as close to 0 as possible. Switch controllers and win the match to unlock this achievement.
If you don't have a second controller, try finding a friend to boost in a private match online.