Barry Corr goal the difference as Blues make it three consecutive victories.
Daniel Bentley equalled Mervyn Cawston’s record of ten consecutive home clean sheets as Blues clocked up a 1-0 win over Tranmere Rovers at Roots Hall.
Phil Brown made one change to the side that won at Hartlepool United on Easter Monday, with Gary Deegan coming in to replace the injured Ryan Leonard.
Will Atkinson seized upon an early defensive error, before Michael Timlin played in Jake Cassidy as Southend started with attacking intent.
Kayode Odejayi then tested Blues keeper Bentley in the 5th minute with a low effort after managing to escape the attention of the Blues back-line.
A deep cross from Danny Holmes picked out Cole Stockton at the far post, but the Tranmere frontman’s headed attempt looped over Bentley’s goal.
Corr was claiming for a penalty in the 31st minute after being taken down with a challenge from behind, but referee Graham Horwood waved away the claims of the Blues striker.
Tranmere full-back Holmes then took aim from range, letting fly with a low effort from 25 yards. Bentley was equal to the effort and turned the ball away for a corner kick.
A low ball to the front post from a Will Atkinson corner found Corr in space on the edge of the six-yard box, enabling the forward to put Blues in front at Roots Hall.
Corr caressed a curling effort past Tranmere stopper Owain Fon Williams, to net his 15th goal of the season, and his ninth in his last 11 appearances for Southend.
There was one final chance before the interval, with Atkinson’s corner finding the head of Adam Barrett, only for his attempt to skim off of his head and wide of goal.
Blues started the second half in the manner they had finished the first, and Cassidy almost netted against the Birkenhead club - who he represented between 2012 and 2014 in three loan spells.
Only a sprawling save from Fon Williams denied Cassidy’s rising effort, as the on-loan Wolverhampton Wanderers striker went in search of his first goal in Southend colours.
A cross from Timlin looked to pick out Atkinson at the back post, but the Tranmere stopper was alert once again to clear the danger.
A corner from Atkinson was then headed just wide by Barrett, before the Blues midfielder was brought down in the penalty area by Michael Ihiekwe but denied what looked a clear penalty.
Bolger went into the book in the 60th minute of the game, after a foul on former Southend man Marc Laird.
Tranmere Rovers boss Micky Adams then introduced Jennison Myrie-Williams and Rory Donnelly in place of Max Power and Josh Thompson.
Southend stood firm in the face of three Tranmere corners in quick succession, before Barry Corr made way for Joe Pigott with 21 minutes of regulation time remaining.
David Worrall then replaced on-loan Nottingham Forest winger Stephen McLaughlin, providing an instant impact with an inviting floated ball across the face of goal.
Rovers boss Adams then made his final change of the afternoon in the 73rd minute, as Cole Stockton departed to enable Jake Kirby to enter the action.
Tranmere defender Donacien then went into the book for holding back the advancing Pigott.
Pigott then continued to work the Tranmere back-line, drifting off the left-hand side before firing a low effort that was held by Fon Williams in the Tranmere goal.
Rovers substitute Donnelly then picked up a yellow card after kicking the ball away.
Some great individual skill from Atkinson on the right flank threatened to create a second goal for Blues in injury time, but it ended 1-0 as Blues chalked up their third straight win in League Two.
SOUTHEND UNITED: Bentley; White, Bolger, Barrett, Coker; Atkinson, Deegan, Timlin, McLaughlin (Worrall - 72’); Cassidy, Corr (Pigott - 69’).
Unused Subs: T. Smith, Binnom-Williams, Payne, Hurst, Weston.