The league pacesetters endured a frustrating afternoon as they were held to a goalless draw by Gillingham at Ashton Gate, but Swindon Town enjoyed a better day after Raphael Branco's early goal helped the Wiltshire club to victory at Port Vale.
Barnsley's resurgence under new manager Lee Johnson continued as he guided the Tykes to victory against his former club Oldham Athletic. Two goals from Lewin Nyatanga and one from Conor Hourinhane were enough for the Yorkshire men to register a sixth consecutive win.
Peterborough United are behind Barnsley on goals scored after Luke James and Conor Washington scored for Posh in a 2-0 win at Doncaster Rovers, their fourth straight victory since the dismissal of Darren Ferguson as manager last month.
Both Barnsley and Peterborough are a point behind Sheffield United, who retain fifth place despite being held to a draw by lowly Scunthorpe United at Glanford Park.
At the bottom of the table, Leyton Orient's bid for survival was boosted by a 3-0 win against fellow strugglers Yeovil Town, with Chris Dagnall, Ryan Hedges and Jobi McAnuff getting on the scoresheet for the O's.
However, Orient were denied the opportunity to move out of the bottom four when Frank Nouble's strike gave Coventry City their first victory under new manager Tony Mowbray at playoff-chasing Chesterfield.
Izale McLeod's late penalty saw Crawley Town edge a five-goal thriller against second-bottom Colchester United, which keeps the Sussex club firmly in touch with the sides outside the relegation places.
Results in full: Bristol City 0–0 Gillingham, Chesterfield 2–3 Coventry City, Colchester United 2–3 Crawley Town, Doncaster Rovers 0–2 Peterborough United, Fleetwood Town 1–0 Rochdale, Leyton Orient 3–0 Yeovil Town, Notts County 1–1 Bradford City, Oldham Athletic 1–3 Barnsley, Port Vale 0–1 Swindon Town, Preston North End 5–1 Crewe Alexandra, Scunthorpe United 1–1 Sheffield United, Walsall 1–1 MK Dons