Danny Allsopp allayed fears over his form with a goal in the 26th minute and Stuart Green wrapped it up with a superb individual effort from 25 yards in first half stoppage time.
But it was Oldham that produced the first real chance of the game when Dean Holden put his shot over the bar in the second minute following a fumble by City keeper Boaz Myhill.
But The Tigers quickly regained their composure and began to pass the ball around neatly.
After eight minutes Green saw a powerful shot saved and Nick Barmby in particular was causing problems for the Oldham defence.
Allsopp drew first blood with his opening goal of the season after Barmby cleverly robbed Holden of the ball just outside the area and played the tall striker in.
After 31 minutes, former Tiger John Eyre's cross played in David Eyres who agonisingly saw his header hit the bar and rebound back out with Myhill beaten.
After the restart Leon Cort brought a good save from Leslie Pogliacomi as the Latics defence looked increasingly panic stricken.
The only blow for City was an injury to Myhill who limped off late on enabling Matt Duke to experience his first taste of league football.
But it later emerged that Myhill was only suffering from a bruised buttock and he should be back in action when Hull meet Wrexham in the Carling Cup on Tuesday.