All 4 Vs achievements (1v1, 2v2, 3v3 and 4v4) can be done solo with one controller and no bots:
Setup an exhibition match and set the team size to the appropriate size for the achievement and leave it 'No Bots' then in the Mutator settings set 'Max Score' to '1 Goal' then begin the match.
to auto join the teams and just accelerate sing forwards, do not boost as the ball wont go in
. Skip the replay and the achievement is yours.