Promotion-chasing Port Vale's slump continued as Southend kept their play-off hopes alive with a narrow win.
Sean Clohessy fired the Shrimpers in front from the spot after Darren Purse had fouled Matt Lund in the area.
Britt Assombalonga then turned Purse inside out to find space for the second before Ryan Leonard stuck the Vale bar, which encouraged the home supporters to boo off their side at half-time.
Lee Hughes flicked in Chris Shuker's cross but Vale are now winless in four.
- Micky Adams' faltering Port Vale have now won just once in seven matches, taking just one point from a possible 12.
Hughes' 64th-minute strike was his 11th goal of the season (and the the 36-year-old veteran's fifth in 10 matches for Vale).
But Vale's 27-goal top scorer Tom Pope has not scored now in nine games. And, although Micky Adams' men remain second, they have allowed the chasing teams in the play-off pack to close the gap.
Eighth-placed Southend had taken just five points out of the previous 18 on offer.
Yet, despite being without manager Paul Sturrock because of illness, their fourth win in six away games lifts them back to within five points off the play-off positions, with a game in hand on seventh-placed Exeter City.
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Live Text Commentary
Full Time The referee blows for the end of the match.90:00 +3:25
Neil Harris has an effort at goal from deep inside the area missing to the right of the goal.90:00 +2:29
Shot on goal by Sam Morsy from just inside the area goes over the target.90:00 +1:39
Free kick awarded for an unfair challenge on Neil Harris by Anthony Griffith. Free kick taken by Anthony Straker.90:00 +0:44
Outswinging corner taken right-footed by Chris Birchall from the right by-line, clearance by Luke Prosser.89:16
Neil Harris decides to take a short corner.88:32
Neil Harris decides to take a short corner.87:40
Sean Clohessy fouled by Richard Duffy, the ref awards a free kick. Free kick taken by Sean Clohessy.86:13 Substitution
Substitution Calvin Andrew comes on in place of Chris Shuker.86:13
The referee blows for offside against Neil Harris. Indirect free kick taken by Chris Neal.84:32
Outswinging corner taken right-footed by Kevan Hurst played to the near post.83:48
Unfair challenge on Matthew Lund by Lee Hughes results in a free kick. Free kick taken by Matthew Lund.83:12 Substitution
Substitution Barry Corr replaces Britt Assombalonga.82:39 Substitution
Substitution (Southend) makes a substitution, with Neil Harris coming on for Bilel Mohsni.81:15
Free kick awarded for a foul by Ryan Cresswell on Lee Hughes. Chris Shuker takes the indirect free kick.81:15 Booking
Booking Matthew Lund shown a yellow card.79:41
Unfair challenge on Ryan Cresswell by John McCombe results in a free kick. Paul Smith takes the free kick.78:58
Chris Birchall takes a outswinging corner to the near post, clearance made by Matthew Lund.76:06
Chris Shuker takes the inswinging corner, clearance by Matthew Lund.75:07
Chris Birchall takes a shot. Save made by Paul Smith.
Unfair challenge on Anthony Griffith by Ryan Leonard results in a free kick. Chris Birchall takes the indirect free kick.72:11
Corner taken right-footed by Chris Shuker from the right by-line to the near post, clearance by Bilel Mohsni.71:53
The referee gives a free kick against Britt Assombalonga for handball. Richard Duffy takes the free kick.66:37
Matthew Lund takes a shot. Robert Taylor gets a block in.66:01
Outswinging corner taken by Kevan Hurst from the right by-line, Chris Neal makes a save.65:29
Outswinging corner taken right-footed by Kevan Hurst from the right by-line to the near post, Liam Chilvers manages to make a clearance.63:15
Assist by Chris Shuker.63:15 Goal scored
Goal! - Lee Hughes - Port Vale 1 - 2 Southend Lee Hughes scores a headed goal from inside the penalty area. Port Vale 1-2 Southend.62:23
Chris Shuker takes a outswinging corner.57:29
Foul by Liam Chilvers on Michael Spillane, free kick awarded. Ryan Cresswell takes the direct free kick.54:25
Anthony Straker fouled by Chris Birchall, the ref awards a free kick. Paul Smith restarts play with the free kick.53:23 Booking
Booking John McCombe is cautioned.53:09
Free kick awarded for an unfair challenge on Britt Assombalonga by John McCombe. Kevan Hurst takes the direct free kick.50:13 Booking
Booking Caution for Sam Morsy.49:27
Sean Clohessy fouled by Sam Morsy, the ref awards a free kick. Sean Clohessy takes the free kick.48:14
Foul by Britt Assombalonga on Liam Chilvers, free kick awarded. Direct free kick taken by Sam Morsy.46:01 Booking
Booking The referee shows Lee Hughes a yellow card for unsporting behaviour.45:57
Lee Hughes is penalised for a handball. Indirect free kick taken by Paul Smith.45:42
Chris Birchall fouled by Bilel Mohsni, the ref awards a free kick. Chris Birchall restarts play with the free kick.45:01
The referee blows his whistle to start the second half.45:01 Substitution
Substitution Darren Purse goes off and John McCombe comes on.45:01 Substitution
Substitution Chris Birchall replaces Jennison Myrie-Williams.45:00 +1:37 Half time
Half Time The whistle is blown to end the first half.45:00 +0:54
Ryan Leonard takes a shot.42:32
Anthony Straker challenges Chris Shuker unfairly and gives away a free kick. Jennison Myrie-Williams takes the direct free kick.40:10
Lee Hughes concedes a free kick for a foul on Ryan Cresswell. Paul Smith takes the indirect free kick.35:44
Lee Hughes gives away a free kick for an unfair challenge on Sean Clohessy. Paul Smith restarts play with the free kick.30:25
Assist on the goal came from Matthew Lund.30:25 Goal scored
Goal! - Britt Assombalonga - Port Vale 0 - 2 Southend Britt Assombalonga gets on the score sheet with a brilliant goal from inside the box to the top left corner of the goal. Port Vale 0-2 Southend.28:29
Outswinging corner taken left-footed by Jennison Myrie-Williams, Ryan Cresswell manages to make a clearance.27:20
Corner taken left-footed by Jennison Myrie-Williams to the near post, clearance by Matthew Lund.23:59
Matthew Lund fouled by Anthony Griffith, the ref awards a free kick. Anthony Straker takes the indirect free kick.22:12
Corner taken right-footed by Kevan Hurst from the left by-line, Chris Neal makes a save.18:44
Michael Spillane gives away a free kick for an unfair challenge on Jennison Myrie-Williams. Darren Purse takes the indirect free kick.18:44 Goal scored
Goal! - Sean Clohessy - Port Vale 0 - 1 Southend Sean Clohessy scores a power penalty. Port Vale 0-1 Southend.17:53 Booking
Booking Booking for Darren Purse for unsporting behaviour.17:44
Darren Purse concedes a Penalty for a foul on Matthew Lund.10:30
Corner from the right by-line taken by Kevan Hurst, clearance made by Chris Neal.9:43
Richard Duffy fouled by Bilel Mohsni, the ref awards a free kick. Richard Duffy takes the free kick.6:36
The official flags Britt Assombalonga offside. Chris Neal takes the indirect free kick.5:45
Corner taken by Kevan Hurst from the left by-line, save by Chris Neal.4:27
Free kick awarded for an unfair challenge on Jennison Myrie-Williams by Britt Assombalonga. Indirect free kick taken by Darren Purse.3:04
Lee Hughes is caught offside. Free kick taken by Paul Smith.1:40
Free kick awarded for an unfair challenge on Ryan Cresswell by Lee Hughes. Paul Smith takes the indirect free kick.0:00
The ref blows the whistle to start the match.
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