Apparently not, as the League One side triumphed 3-2 after an absorbing and aggressive encounter, which left last season's finalists Liverpool knocked out of the FA Cup in the fourth round.
The draw immediately following the final whistle paired the victorious side with the Reds' Merseyside rivals Everton, which otherwise would have been a repeat of last season's semifinal—had Liverpool beaten the team from two leagues below them.
Matt Smith gave the home team a fast start and a lead after two minutes with a towering header before Luis Suarez, captain for the day, passed home the equaliser. Right on halftime Smith doubled his tally for the day and Oldham made it three with a looping header from full-back Reece Wabara straight after the break.
Joe Allen scored with 10 minutes left to ensure the home fans had an anxious wait for the final whistle—but the weekend of giant-killing continued as Oldham defended their lead to go through, and knock out the Reds.
Here are Liverpool players' ratings from the match.
With Pepe Reina still injured, Brad Jones retained his place in goal for Liverpool following his clean sheet against Norwich and some increasingly impressive displays earlier in the campaign.
Today did not follow suit.
Jones was not culpable for either headed goal, but he spilled a very tame effort just before halftime which was turned back into the path of Matt Smith by Lee Croft for a simple tap-in.
The Australian goalkeeper has had more chances given to him this season because of Reina's continual injury woes, but this will be a game he wants to forget quickly. Jones distributed the ball poorly, was not at all assured in the air and failed to communicate effectively with those in front of him.
The Reds started with two teenage full-backs in Andre Wisdom and Jack Robinson.
While Wisdom was quiet and solid, not having too much trouble with the Oldham attack in the first half, he was unable to cut out a cross from deep early after the break which led to the third, and ultimately killer, goal.
On the opposite flank, Jack Robinson simply had a woeful day.
He could not stand up to the pressure at the back, failed to deal with the runners coming in on the diagonal for the crossfield pass and offered nothing in attack, save for two moments in the second half.
One saw him break forward in the opening seconds after the restart, crossing for Fabio Borini to shoot over the bar, and the second saw him waste a great chance to cross by shooting over the bar himself.
For the youngsters in the squad, cup games provide an opportunity to stake a claim for a run in the first team, but Robinson was unable to show his qualities today.
Liverpool chopped and changed the team enough to see a three-quarters new defence, and the centre of the back-line showed the extent of those alterations.
Far from looking confident and domineering, Sebastian Coates was rusty, sluggish and oddly non-physical in his approach to the game. The Uruguayan has barely featured over the past three months and it showed in his game as he was second-best both on the ground and in the air.
Alongside him, Martin Skrtel was marginally better in his aggressiveness and positioning, but between the two they were far too open, allowed Oldham too many chances and did not distribute the ball particularly well.
It can be safely assumed that Daniel Agger and Jamie Carragher will be back in place for the Arsenal match in midweek.
With no Lucas Leiva, and Steven Gerrard only on the bench, the returning Joe Allen was asked to anchor midfield with Jordan Henderson alongside him.
Had the ball spent more time on the ground and in the possession of Liverpool, as was no doubt the plan, this combination might have worked very well. Instead there was a greater urgency to the pressing and tackling of Oldham Athletic—much of which was over the top in terms of legality, and yet went unpunished by the referee.
Even so, Liverpool should have dealt better with their opponents, but they only gained a measure of control when they were already two goals behind and Steven Gerrard came on.
Allen scored his first Liverpool goal with a fine volley via a deflection, but it won't mean particularly much to him given the result. Henderson was brave enough to get on the ball plenty, and was a good performer on the flank when he moved out to right-back.
The photo pretty much sums up the afternoon for Liverpool's wide forwards; they were outmuscled and frustrated by far more physical, bigger opponents.
It was up to Raheem Sterling and Fabio Borini to outwit and beat that approach, but neither got to grips with the game and were replaced in the second half.
Borini was almost completely anonymous in the first period and spooned a great chance over the bar just 20 seconds after the restart, moments before Oldham's third goal went in.
Sterling had flashes of impact in the game but he was mostly notable for running a tight disciplinary line after being booked just minutes into the game and then committing a couple more fouls before halftime.
Neither had any telling impact in the wide areas of the pitch or down the channels.
With Liverpool starting with a very attack-minded lineup, Luis Suarez—captain for the first 55 minutes or so—played a No. 10 role in between midfield and attack, while Daniel Sturridge operated as the central striker once more.
Chances did not fall frequently to either player, though, again they showed some nice link-up play in the first half. A couple of snap-shots on the turn did not yield the record-breaking fourth goal in four games that Sturridge wanted, meaning former Red Dean Bouzanis became the first goalkeeper to prevent Sturridge scoring since he moved to Liverpool.
Suarez equalised with a fine run and finish after an attempted pass was diverted back to him, and he now has 21 goals in all competitions this season.
The effectiveness of both attackers was reduced after the break when Oldham sat back and the Reds tried time and time again to attack down the flanks, with the defence sticking tight to deny space or shooting opportunity inside the penalty area.
Liverpool's tempo and control of the game was instantly lifted when captain Steven Gerrard entered the game, but should it have had to come to that?
Playing high in the midfield line, Gerrard sought to free those in wide areas and get involved in building attacks centrally—and he almost rescued the draw for Liverpool with a thunderous strike from range which clattered back off the crossbar.
He also saw two other shots blocked by sprawling defenders, and was certainly the Reds' most potent weapon after the break.
The other two subs, Stewart Downing and Jonjo Shelvey, also had a positive influence on Liverpool's play but were unable to find the telling pass or shot themselves. Downing stretched play and ran at the full-backs without managing to penetrate accurately enough, while Shelvey upped the tempo further and attempted a long-range strike which flew over.
Unused subs: Peter Gulacsi, Jamie Carragher, Suso, Lucas Leiva.