Oxford missed a series of chances but finally took the lead when Steve Kinniburgh set up Batt who slotted in.
The visitors had a great chance to equalise late on but Shaun Densmore saw his shot cleared off the line.
The win sees Oxford extend their lead at the top of the Blue Square Premier to eight points.
Oxford Utd: Clarke, Batt, Foster, Creighton, Kinniburgh, Murray (Perry 86), Bulman, Clist, Green (Cook 77), Constable, Midson (Deering 61). Subs Not Used: Turley, Sandwith.
Goals: Batt 65.
Altrincham: Coburn, Doughty, Young, Williams, Densmore, Burns, Danylyk, Lawton (Welch 80), Bryan (Pearson 53), Little, Clee. Subs Not Used: Saunders, Bennett, Smart.
Booked: Coburn, Lawton, Young.
Ref: I Cooper (England).