Somewhat easy, kinda fast way. The person who wants the achievement is Maxi with Y+B (BK) hot keyed. The other person is Yoshimitsu with X+Y (AB) hot keyed. Battle Time 80, Battle Count 5. Have Maxi spam (BK) and when Yoshimitsu gets low on health, use down (AB) then hold down (AB) to regenerate health. Repeat untill time runs out.