Goals from Mark Gower and Wayne Gray handed Southend a win against high-flying Northampton.
But the Cobblers will be left wondering how their three-game unbeaten run came to an end after creating a string of chances amid a decent performance.
Freddy Eastwood attempted to claim the first blood for Southend but his tame 25-yard shot was easily held by Paul Rachubka.
The visitors responded with Josh Low's cross from the right causing trouble in the Blues' rearguard. The ball eventually fell to David Rowson, whose shot was saved by Daryl Flahavan.
Eastwood blasted over a 25-yard shot after good work by Lewis Hunt, before Low found Rowson again, but he scooped his shot over from 12 yards.
Those wasted chances were punished after 27 minutes when an Eastwood ball deflected into Gower's path and he rifled a 25-yard shot past a diving Rachubka.
Northampton were handed a great chance to equalise from the penalty spot. Che Wilson brought down Eric Sabin, but Flahavan turned Martin Smith's spotkick out for a corner after 38 minutes.
McGleish then missed an open goal and Sabin's shot was deflected off team-mate Lee Williamson.
The Cobblers started the second half the stronger side with Sabin setting up Low for a rising 20-yard shot that was inches wide.
Another period of industry saw Pedj Bojic rifling in a cross from the right which was met by an unmarked Smith. But his glancing header went wide.
Southend struggled to breach the Town defence and when Wayne Gray put Eastwood clear his goal was ruled out for offside.
But Gray doubled the Shrimpers' advantage after 76 minutes. He was put clear by Eastwood and beat Fred Murray to shoot past Rachubka.
The visitors pulled a goal back on 87 minutes when Sabin's low shot beat Flahavan at his near post.
And the impressive Low blew a chance to get a stoppage time equaliser when he failed to control the ball when well placed.