County stun high-flying Oxford
Promotion-chasing Oxford lost 3-2 at Newport, while Rochdale and Burton shared a 1-1 draw in League Two on Tuesday night.
Oxford suffered their first away defeat of the League Two season, going down 3-2 to Newport in a pulsating game at Rodney Parade.
James Constable gave the Us a 14th-minute lead against the run of play, rifling home Dave Kitson's cross, but Rene Howe equalised on the stroke of half-time.
Ryan Burge gave Newport the lead, Chris Zebroski tapped into an empty net and, although Alfie Potter pulled one back late on, Oxford could not find an equaliser.
Fourth-placed Rochdale could not take full advantage as a home draw with sixth-placed Burton took them only level on points with Oxford, albeit with a game in hand.
Burton took a 35th-minute lead after Gary Alexander's header was saved, but Rochdale's relentless pressure was finally rewarded when Burton goalkeeper Rob Lainton fumbled George Donnelly's weak shot into his own goal.
Southend remained six points clear in the final play-off place after a 1-1 draw with Hartlepool.
Barry Corr put the Shrimpers ahead, tapping in Kevan Hurst's cross, but Bradley Walker equalised just before the hour with an excellent volley.
Southend have 48 points, with both Newport and Hartlepool on 42.
There was yet another 1-1 draw in the game between Exeter and Morecambe, which finished in controversial circumstances.
Tom Nichols' early opener was cancelled out by Morecambe's Padraig Amond (54) but the drama came in stoppage time when referee Andy D'Urso appeared to award Exeter a penalty.
Morecambe's Jamie Devitt was sent off in the resulting fracas but, with John O'Flynn waiting to take the penalty, D'Urso reversed his decision after consulting with his assistant and instead awarded the visitors a free-kick.
Accrington drew 0-0 with Bury in the evening's other game, despite having Lawrie Wilson sent off in the 31st minute.