Britt Assomobalonga's impressive strike pegged back Plymouth as Southend finished the match with 10 men.
Alex MacDonald slid the ball under Shrimpers goalkeeper Daniel Bentley to give the hosts the lead shortly after the break.
But Assomobalonga beat his marker with a smart turn, raced away down the right and fired the ball in for 1-1.
Paris Cowan-Hall was denied a late Plymouth winner, before Barry Corr saw red for a foul on Darren Purse.
VIEW FROM THE DRESSING ROOM
Plymouth Argyle manager Carl Fletcher tells BBC Radio Devon:
"We played well in the first half and in bits of the second, but I felt it was an opportunity missed.
"Southend will be there at the end of the season. They've won four of their last five games and we knew it was going to be tough. They've got some big players and we played really well today.
"We were working all week trying to get wide men in pockets. We were working on our movement of our strikers down the channels and we worked that well.
"I've got some good players here and a good squad. I'll defend them until I'm blue in the face."
Southend United manager Paul Sturrock told BBC Essex:
"I was disappointed with our first 45 minutes. There was a lethargy about us, we let things bounce, our decision making was poor.
"We had a couple of decent chances, but I think they shaded the first half.
"We looked a much stronger team in the second half. We looked the team most likely to score after we equalised.
"We did look as if we were on the ascendancy, think about the amount of corners we had, and we had a couple of half chances we should have done better with."
- 01 Cole
- 02 Berry Booked
- 04 Blanchard
- 05 Purse
- 14 Bhasera
- 03 Williams
- 06 Hourihane
- 08 Young
- 11 Feeney (Cowan-Hall - 65' )
- 18 Madjo (Griffiths - 65' )
- 32 MacDonald (Chadwick - 90' )
- 13 Chenoweth
- 17 Nelson
- 27 Gurrieri
- 07 Cowan-Hall
- 09 Chadwick
- 10 Griffiths
- 21 Lecointe
- 17 Bentley
- 02 Clohessy
- 06 Cresswell
- 16 Prosser
- 23 Barker
- 08 Timlin
- 11 Martin (Leonard - 46' Booked )
- 14 Hurst
- 19 Spicer (Corr - 68' Dismissed )
- 20 Assombalonga
- 24 Benyon (Eastwood - 64' )
- 31 Smith
- 03 Straker
- 05 Coughlan
- 18 Leonard
- 30 Woodyard
- 07 Eastwood
- 10 Corr
Live Text Commentary
Free kick taken by Jake Cole.90:00 +2:44 Booking
Booking Ryan Leonard is cautioned by the ref for unsporting behaviour.90:00 +2:38
Free kick awarded for an unfair challenge on Paris Cowan-Hall by Ryan Leonard.89:46 Substitution
Substitution Nick Chadwick on for Alex MacDonald.89:01
Rhys Griffiths challenges Ryan Cresswell unfairly and gives away a free kick. Free kick taken by Daniel Bentley.86:05
Shot from just outside the box by Durrell Berry goes over the bar.84:34 Full time
Full Time The game is over, as the referee blows his whistle.84:20
Outswinging corner taken right-footed by Kevan Hurst.80:54 Dismissal
Dismissal Barry Corr receives a red card.80:40
Darren Purse fouled by Barry Corr, the ref awards a free kick. Jake Cole takes the free kick.79:54
Michael Timlin concedes a free kick for a foul on Alex MacDonald. Conor Hourihane takes the free kick.79:26
Corner from the right by-line taken by Kevan Hurst, clearance made by Maxime Blanchard.75:45
Michael Timlin challenges Paris Cowan-Hall unfairly and gives away a free kick. Shot comes in from Robbie Williams from the free kick, clearance made by Freddy Eastwood. Corner taken by Conor Hourihane, clearance by Ryan Cresswell.75:07
Barry Corr concedes a free kick for a foul on Alex MacDonald. Jake Cole restarts play with the free kick.74:09
Britt Assombalonga is caught offside. Jake Cole restarts play with the free kick.73:06
Effort on goal by Britt Assombalonga from inside the box misses to the right of the target.72:39
Unfair challenge on Chris Barker by Alex MacDonald results in a free kick. Direct free kick taken by Daniel Bentley.72:01
Britt Assombalonga takes a shot from close range clearing the crossbar.70:54
Unfair challenge on Kevan Hurst by Conor Hourihane results in a free kick. Direct free kick taken by Kevan Hurst.69:31
Free kick awarded for an unfair challenge on Paris Cowan-Hall by Luke Prosser. Conor Hourihane delivers the ball from the free kick left-footed from right wing, save by Daniel Bentley.
Effort on goal by Kevan Hurst from just outside the penalty area goes harmlessly over the target.67:21
Foul by Britt Assombalonga on Maxime Blanchard, free kick awarded. Direct free kick taken by Jake Cole.67:21 Substitution
Substitution Barry Corr on for John Spicer.65:29
Corner taken by Conor Hourihane, Rhys Griffiths has a headed effort at goal from deep inside the area missing to the left of the target.64:13 Substitution
Substitution Rhys Griffiths joins the action as a substitute, replacing Guy Madjo.64:13 Substitution
Substitution Paris Cowan-Hall joins the action as a substitute, replacing Warren Feeney.63:03 Substitution
Substitution Freddy Eastwood on for Elliot Benyon.59:31
Free kick taken by Daniel Bentley, Ryan Cresswell takes a shot. Jake Cole makes a save.59:31 Booking
Booking Durrell Berry booked.59:29
Michael Timlin fouled by Durrell Berry, the ref awards a free kick.58:17
Darren Purse fouled by Kevan Hurst, the ref awards a free kick. Direct free kick taken by Jake Cole.53:54
The assist for the goal came from Ryan Leonard.53:54 Goal scored
Goal! - Britt Assombalonga - Plymouth 1 - 1 Southend Britt Assombalonga grabs a goal from inside the penalty box to the bottom left corner of the goal. Plymouth 1-1 Southend.49:20
Assist by Guy Madjo.49:20 Goal scored
Goal! - Alex MacDonald - Plymouth 1 - 0 Southend Alex MacDonald grabs a goal from inside the penalty box to the bottom right corner of the goal. Plymouth 1-0 Southend.48:34
Outswinging corner taken right-footed by Kevan Hurst, Ryan Cresswell produces a header from inside the six-yard box that clears the bar.45:01 Half time
Half Time The referee calls an end to the first half.45:01 Substitution
Substitution David Martin goes off and Ryan Leonard comes on.40:57
Outswinging corner taken left-footed by Conor Hourihane, Header from deep inside the penalty area by Maxime Blanchard goes harmlessly over the crossbar.40:39
Unfair challenge on Luke Prosser by Guy Madjo results in a free kick. Free kick taken by Luke Prosser.39:20
Britt Assombalonga takes a shot. Save by Jake Cole.36:35
Onismor Bhasera fouled by Sean Clohessy, the ref awards a free kick. Alex MacDonald crosses the ball in from the free kick, Ryan Cresswell manages to make a clearance. Outswinging corner taken from the right by-line by Alex MacDonald, Ryan Cresswell makes a clearance.32:59
The assistant referee signals for offside against Warren Feeney. Indirect free kick taken by Daniel Bentley.31:05
Effort from the edge of the area by Onismor Bhasera goes wide of the right-hand upright.30:00
Free kick awarded for an unfair challenge on Ryan Cresswell by Onismor Bhasera. Daniel Bentley takes the direct free kick.29:21
Unfair challenge on Guy Madjo by Ryan Cresswell results in a free kick. Free kick taken by Alex MacDonald.25:39
Elliot Benyon takes a shot. Save made by Jake Cole.23:03
Sean Clohessy gives away a free kick for an unfair challenge on Warren Feeney. Shot comes in from Alex MacDonald from the free kick.22:09
Conor Hourihane has a shot on goal from outside the area which misses right.21:12
The ball is delivered by Alex MacDonald, Headed effort from deep inside the area by Onismor Bhasera misses to the left of the goal.18:50
Outswinging corner taken right-footed by Alex MacDonald, clearance by Elliot Benyon.18:15
The referee blows for offside. Jake Cole restarts play with the free kick.17:54
Onismor Bhasera takes a shot. Save made by Daniel Bentley.16:43
Inswinging corner taken right-footed by Kevan Hurst, clearance by Darren Purse.15:21
Darren Purse fouled by Britt Assombalonga, the ref awards a free kick. Jake Cole takes the free kick.14:38
The ball is crossed by Sean Clohessy, Headed effort from inside the box by Britt Assombalonga misses to the right of the target.13:34
Unfair challenge on Darren Purse by Elliot Benyon results in a free kick. Jake Cole takes the indirect free kick.11:56
Durrell Berry challenges Elliot Benyon unfairly and gives away a free kick. Direct free kick taken by Kevan Hurst.7:45
The offside flag is raised against Britt Assombalonga. Indirect free kick taken by Jake Cole.6:58
David Martin gives away a free kick for an unfair challenge on Onismor Bhasera. Robbie Williams takes the direct free kick.6:17
Centre by Robbie Williams, Headed effort from inside the area by Onismor Bhasera misses to the right of the target.4:20
Free kick awarded for an unfair challenge on David Martin by Durrell Berry. The free kick is delivered right-footed by Kevan Hurst from left wing, Maxime Blanchard manages to make a clearance.1:10
Corner taken left-footed by Conor Hourihane.0:00
The game begins.
The referee gets the second half started.
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