Having been forced into a replay, the Toffees were far more authoritative the second time around, and—although Oldham never gave in—the hosts were relatively comfortable throughout.
Kevin Mirallas opened the scoring with 15 minutes on the clock, prodding home a sumptuous cross from Darron Gibson.
After a pair of debatable penalty shouts for either side, Everton were awarded a spot-kick on 34 minutes, which Leighton Baines duly converted.
Just after the hour mark, Leon Osman glanced in a third for the Toffees before Matt Smith powered home a consolation that kept the tie competitive.
Here are six Everton-related talking points to emerge from this fixture.
Many Evertonians are convinced this will be the last season Marouane Fellaini struts his stuff on the Goodison Park turf, yet that may not be as disastrous as it sounds.
The Belgian is certainly an elite player who Everton have done well to hold on to; however, playing in an attacking role he often leaves his side appearing a little too predictable. This in turn can leave the Toffees struggling, especially against physical defenders, and it hasn't helped the form of Nikica Jelavic.
Against Oldham, Leon Osman, Steven Pienaar and Kevin Mirallas formed a fluid trio behind Jelavic, all of whom were comfortable right across the field, seamlessly interchanging with each other.
Everton's attack appeared more balanced as a result and, given time, this approach would further develop as it progresses. This was how the side lined up against West Brom—coincidentally the Toffees' last win—with Fellaini then deployed in his more favoured role of defensive midfield.
If Everton are to depart with Fellaini, while it will clearly be a blow, it could actually improve the style in which the Toffees play and allow a more fluent method to form over time.
Given the attractive fee they would receive for the Belgian, and the fact they have generally prospered in his absence this season, it may not be quite the catastrophe many anticipate.
One frustration from tonight's endeavours was the continued struggles of Nikica Jelavic.
After 11 goals in 16 games last season, and another five in 11 at the start of this campaign, the Croatian's been on a truly barren run of form, with just two goals in his last 20 appearances.
Sadly even League One Oldham could not provide any respite.
Few can criticise his work-rate, but his confidence is visibly down leaving him hashing at half chances and frequently miss-controlling with an increasingly dire touch.
He was inches away from getting a touch on Leon Osman's goal, and the vast majority of supporters would have preferred the ball to brush off his leg to end this drought.
For Everton to finish this season on a high it's simply imperative Jelavic rediscovers his scoring touch.
By slotting home his side's third goal of the night, Leon Osman notched up his 50th strike in an Everton jersey.
It's also his seventh goal of the season, a milestone the England man's never yet surpassed in Everton colours, reaching it three times before, in 2004/05, 2007/08 and 2008/09.
While Osman doesn't quite seem in the form he was towards the start of the season, he's enjoyed a hugely successful campaign, playing as central as he's ever appeared for the Toffees.
With several games still to go he should fancy his chances of reaching double figures, which would be a fine contribution to a side often struggling for goals.
Everton are renowned for having one of the more feared left flanks in the Premier League, with Leighton Baines and Steven Pienaar, at times, unplayable together.
As a result, the Toffees attack down the left third of the field 43 percent of the time (the highest in the Premier League) and venture forward on the right just 30 percent (the lowest in the Premier League).
However, back in August and September there were high hopes some considerable production could stem from the right.
Injuries to both players rather disrupted their progress, but the pair spent much of this game reacquainting with each other.
As a result, the Toffees' right was equally as dangerous and contributed to both opening goals.
Mirallas scored the first goal himself, after fine work between Coleman, Phil Neville and the eventual crosser, Darron Gibson, and the second goal came after Coleman ran free and delivered.
The Irishman and his Belgian teammate created four chances from the right, two each, while just one opportunity was farmed out from the usually prolific left.
David Moyes will no doubt be furious at the way his side conceded, once again falling asleep at a set-piece situation and seeing an opponent head in.
Communication seemed to fail between Sylvain Distin and his fellow defenders as Matt Smith strode in unchallenged to head home his second goal against the Toffees.
While the finish was not consequential, it's become almost comical just how often Everton are breached in the air, especially via set-pieces.
That was the case in the initial tie, with Smith again the benefactor, and—as was also evident against Norwich at the weekend—it's plagued the Toffees all season.
Everton could have perhaps been more convincing. They could have been more fluent, more ruthless and tried harder to play their way into form. However, all that matters from this encounter is that they remain in the FA Cup.
A home tie with Wigan is now all that separates the Toffees from a third trip to Wembley in five years which, in all likelihood, leaves them just two wins away from an overdue return to Europe.
It does not have to be repeated just how coveted a trophy is by the club, staff and fans alike, especially given the fragile state of their manager's contract.
David Moyes will be anxious to coax out some more convincing form from his dressing room, but any way his side progress in this competition will be accepted by most.