Burton Albion capitalised on Morecambe's defeat at Tranmere Rovers to move to the top of League Two with victory over Mansfield Town.
Goals in either half from Alexander MacDonald and Callum McFadzean were enough for the Brewers to win 2-1 at Field Mill.
They lead the table on goal difference from Cheltenham Town, who needed a last-minute winner from Koby Arthur to beat Hartlepool United at Whaddon Road.
Shrewsbury Town move into fourth with a 2-0 win over Luton Town, thanks to a brace from Jordan Clark. The Hatters' day was made worse by a late red card for Matt Robinson.
Bury climb into the playoff places after coming from behind to beat Accrington Stanley at Gigg Lane, with Danny Mayor's strike just after the hour mark proving decisive.
Portsmouth's unbeaten run under manager Andy Awford was brought to an end as Andy Sandell's dazzling free-kick in the 84th minute gave Newport County victory at Fratton Park.
Pompey are still in the top seven, but they have Northampton Town close behind after the Cobblers snatched a late victory over Exeter City at Sixfields, with Marc Richards getting the vital goal.
At the foot of League Two, Oxford United halted a run of eight straight defeats with a thrilling 3-3 draw at home to Dagenham and Redbridge. Danny Hylton scored twice for the home side.
Carlisle United's poor start to the season continued as they were beaten 5-0 at Cambridge United. Robbie Simpson and Jayden Stockley both bagged braces for the hosts.
Elsewhere, Charlie Lee's 74th-minute goal helped Stevenage win 3-2 at AFC Wimbledon, and York City and Wycombe Wanderers played out a goalless draw.
Results in full: AFC Wimbledon 2-3 Stevenage, Bury 2-1 Accrington Stanley, Cambridge United 5-0 Carlisle United, Cheltenham Town 1-0 Hartlepool United, Mansfield Town 1-2 Burton Albion, Northampton Town 1-0 Exeter City, Oxford United 3-3 Dagenham & Redbridge, Plymouth Argyle 2-0 Southend United, Portsmouth 0-1 Newport County, Shrewsbury Town 2-0 Luton Town, Tranmere Rovers 2-1 Morecambe, York City 0-0 Wycombe Wanderers
