Conor Thomas' second-half penalty was enough to seal a 1-0 win for Cheltenham over Southend and move Michael Duff's side top of League Two.
The midfielder converted from the spot in the 53rd minute after Leicester loanee Callum Wright was tripped in the box by Shaun Hobson.
The first period had seen Matty Blair blaze over the bar for Cheltenham after a low cross from Wright fell to him in the box.
Charlie Raglan also got his head to a couple of long throw-ins from Ben Tozer, but neither troubled keeper James Montgomery.
Southend's lone frontman Emile Acquah directed a header from Ashley Nathaniel-George's cross over the bar four minutes into the second half.
A curling shot from Sam Smith was gathered safely by a diving Montgomery in the 62nd minute and Andy Williams sent an overhead kick just wide of the near post as Cheltenham looked for a second.
The closest Southend came to a leveller was substitute Simeon Akinola's glancing header which fell just wide of the left post in the 84th minute.