Fabien Robert goal the difference at a baking Roots Hall.
Southend United are still looking for their first win of the season after suffering a narrow 1-0 defeat to Swindon Town at a sun-drenched Roots Hall.
Fabien Robert's close range strike proved the difference midway through the second half as he prodded home, whilst Swindon goalkeeper Lawrence Vigouroux produced several fine stops to deny Blues taking not just a point, but all three for their efforts.
Blues boss Phil Brown handed starts to Luke Prosser, Jack Payne and Noel Hunt, with Cian Bolger injured, Joe Pigott on the bench and Kevan Hurst out of the squad.
New signing Luke O'Neill, who signed earlier in the day, took his place on the bench.
The visitors started brightly, and Dan Bentley has to be alert to push away a bouncing effort from Nathan Byrne after only four minutes of play.
Swindon had to make an early change inside the opening ten minutes as right back and captain Nathan Thompson hobbled off the pitch and was replaced by Drissa Traore.
Blues' best chance of the half fell to Hunt.
He controlled a cross-field ball from John White excellently, cut in but saw his stike from 25 yards crash back off the post before being cleared.
With half time approaching, Robert had two chances to open the scoring for Swindon.
Firstly, he got on the end of a Brandon Ormonde-Ottewill cross but powerfully headed wide.
And moments later, he attempted to place the ball past Bentley from the edge of the box but the ball fell just wide of the intended target.
After the break, Hunt had an effort inside the opening 30 seconds of the half after the Irish forward was put through, but his low drive was smothered by Robins custodian Vigouroux.
Five minutes later and Blues were handed a glorious chance to break the deadlock.
Michael Timlin played in David Worrall, whose cross was nodded down by Hunt into the patch of Payne, but the midfielder could only volley wide of Vigouroux's goal from ten yards out.
Three minutes after the hour mark, the Robins took the lead through Robert.
The midfielder snuck in behind Ben Coker after Nathan Byrne's pass and slotted into the net from close range.
It was a bitter blow for the Blues, who had had the majority of the play in the second half.
On 65 minutes, Byrne went on a solo run before slashing wide of Bentley's goal from the edge of the box.
Phil Brown made a double change with 18 minutes left, throwing on Myles Weston and Anthony Wordsworth in place of Timlin and Will Atkinson respectively.
With ten minutes remaining, Vigououx produced a great stop to tip over substitute Weston's header from close range after a Worrall cross, and soon after, Coker's drive was straight at the Swindon custodian.
Brown's final throw of the dice saw him move to three at the back, as Adam Barrett made way for Joe Pigott, who partnered Hunt up front.
During six minutes of added time, Vigououx denied Pigott from grabbing a late equaliser before Coker smashed an effort narrowly over the bar.
And that was to be the final chances of the game as Blues suffered a home defeat.
Southend United: Bentley; White (c), Barrett (Pigott, 84), Prosser, Coker; Worrall, Leonard, Timlin (Weston, 72), Atkinson (Wordsworth, 72); Payne; Hunt
Unused substitutes: T. Smith, Mooney, Deegan, O'Neill