A penalty after 48 minutes converted by Chris Killen earned Oldham their passage into the second round of the FA Cup, a match that they controlled throughout.
They had just about shaded matters in the opening half having twice produced outstanding saves from man of the match Billy McMahon in the Thurrock goal and got the all important breakthrough just after the resumption.
The impressive Lee Croft, on loan from Manchester City, worked his way into the box although he was out by the edge of the area when a reckless challenge from Steve Heffer sent him sprawling.
Killen stepped forward to slam the ball past McMahon's right although the keeper did get a hand to the ball.
Oldham enjoyed the better chances of a somewhat drab opening 45 minutes with McMahon soon showing his prowess when he tipped away a full-blooded drive from Croft and the Thurrock keeper also did well to deflect a vicious drive from David Lee.
The Essex side had a couple of clear chances, firstly when Tresor Kandol sprung the offside trap after 11 minutes, but then sent his shot hopelessly wide from 18 yards.
His strike partner Cliff Akurang was also presented with a chance when he seized on a bad error from the otherwise reliable Dean Holden, but the home forward blazed over from 20 yards with only the keeper to beat.
The Latics, who were twice Cup semi-finalists in the 90's, totally dominated the game after their goal and Holden and Scott Vernon were both denied by McMahon, while Thurrock were left to rely on half chances in an attempt to claw their way back into the game.
Their best chance though fell to Akurang in the 69th minute, but he somehow screwed his shot wide from just three yards.