Southend required a stoppage-time winner from substitute Sahid Kamara to see off a Boston side now winless in four National League games.
Boston took the lead in the first minute of the game through Ollie Bostock, who caught Southend out with an incredible finish in his first start since returning from international duty with Wales Under-21s.
The Shrimpers got back level just 15 minutes later, though, as Josh Popoola squared to Promise Omochere who tapped home easily.
The game looked destined to end level until the fourth minute of stoppage time, when Kamara picked up the ball on the edge of the box and fired a beautiful strike into the top corner.
Report supplied by PA Media.
