Wins for Doncaster Rovers and Bournemouth saw the top two teams move clear in League One.
Doncaster remain two points ahead at the summit thanks to assistant manager Rob Jones's goal in their 1-0 victory over Tranmere Rovers.
Matt Ritchie scored twice to give Bournemouth a five-point cushion in the automatic promotion places in their 3-1 defeat of Notts County.
Hartlepool moved off the bottom of the table with a 2-0 win over Bury, who take their position, while Colchester eased their relegation worries after beating Leyton Orient 2-1.
Leading goalscorer Paddy Madden netted his 22nd goal of the season in Yeovil Town's 2-1 victory over Shrewsbury to send the Somerset club into third place.
Results in full: Bournemouth 3-1 Notts County, Colchester 2-1 Leyton Orient, Coventry 1-1 Brentford, Doncaster 1-0 Tranmere, Hartlepool 2-0 Bury, MK Dons 0-0 Crawley, Oldham 1-2 Carlisle, Portsmouth 0-0 Stevenage, Preston 3-0 Scunthorpe, Walsall 1-1 Sheffield United, Yeovil 2-1 Shrewsbury
Grant Yardley
