The striker headed home a left-wing cross from Kevan Hurst in the 22nd minute,
and the two teams will now be doing battle again in the play-offs.
In a game of few chances, Corr bagged his 13th goal of the season when Hurst’s excellent cross was headed home by the Irishman from eight yards.
Burton hit back with Lee Bell having a close range shot blocked by Daniel Bentley but Southend were back on top at the start of the second half.
Ryan Leonard had a long range shot smothered by Burton goalkeeper Dean Lyness at the second attempt before Southend skipper John White also had a low effort smothered by Lyness at the second attempt.
Burton then almost bagged a late equaliser when Chris Hussey’s long range free-kick was tipped over by Bentley who secured his 20th goal of the season.