Cheltenham exacted swift revenge for their 2-0 defeat to Southend in mid-December with a 2-1 triumph at Roots Hall.
The Robins raced into a two-goal lead inside the first five minutes, Marlon Pack opening the scoring in the third minute with a 30-yard free-kick over the head of goalkeeper Rhys Evans.
Two minutes later and Wes Thomas doubled the advantage with an angled 20-yard effort that found the bottom corner, with question marks hanging over Evans who should have done better.
Jeff Goulding could have put the visitors 3-0 up but saw his effort well saved by Evans after the striker had beaten three Southend players. Town keeper Scott Brown then comfortably saved Barry Corr's header in what was the home side`s first real effort of the game.
After the break, Evans turned a Michael Pook header over the bar before Corr and substitute striker Matt Paterson were both denied by Brown.
Blues reduced the arrears in the 77th minute when Ryan Hall's centre from the left caused a scramble in the Cheltenham penalty area and Corr stabbed the ball home. But the closest they came to an equaliser was Paterson's volley which was saved by Brown.