Kevan Hurst's 10th goal of the season has given Southend United a narrow half-time lead over League Two promotion rivals Chesterfield at Roots Hall.
The deadlock was broken on 28 minutes when a pass from debutant right-back Luke O'Neill found Anthony Straker, who teed up Hurst to tap home.
Barry Corr came close to doubling Southend's lead soon after, but his 25-yard free kick deflected just wide.
The half ended on a sour note for the hosts as O'Neill, who joined the Shrimpers on a 30-day loan from Burnley earlier this week, limped off the field with a leg injury.
Southend, who began the day fifth in the table, will climb above Chesterfield if they win.
