Danny Wilson returned to old club Swindon and left top of the League One table as Sheffield United earned a 0-0 draw at the County Ground.
The hosts twice hit the woodwork through Matt Ritchie and Gary Roberts, but United almost snatched a last-minute winner themselves when Neill Collins' effort was hacked from the line by Jay McEveley.
Ritchie might have scored in the second minute with a volley which struck the top of the Blades' bar and Roberts struck a post with a shot from just inside the area shortly after the interval.
Wilson's side had few opportunities with Matt Hill and Ryan Flynn heading wide from good positions in the second half.
Swindon manager Paolo Di Canio once strayed two yards on to the pitch to remonstrate with his defence as his team earned a valuable draw to stay in touch with the division's pacesetters.