Southend were unable to halt Sunderland’s momentum as they fell to a 3-0 defeat at the Stadium of Light thanks to goals from George Honeyman, Chris Maguire and Aiden McGeady.
Both sides created chances early but the game suddenly came to a halt when Ben Coker went down with a serious looking knee injury which required him to leave the field on a stretcher.
After the stoppage, Sunderland would go on to break the deadlock through Honeyman, whose glancing header sneaked in at Mark Oxley’s far-post just before the half-hour mark.
Southend had chances to level before the interval but couldn’t take advantage and they went into the break furious at not being given a penalty for a foul on Dru Yearwood.
And after the break, Sunderland would capitalise on that frustration with a thunderous strike from Maguire, that left Oxley with no chance, doubling the home side’s advantage.
Try as they might, Blues couldn’t get a goal back to start any sort of comeback, with Sam Mantom’s close-range header – which was well saved by Jon McLaughlin – the best they could muster.
Sunderland would then wrap up the points with 10 minutes remaining when substitute Aiden McGeady carried the ball forward and fired beyond Oxley to secure the Black Cats' fourth straight win.
That fourth maximum in a row for Jack Ross’ side kept them within touching distance at the top while Southend slipped the 11th in the table ahead of another tough trip to Barnsley next week.