Oldham Athletic's previous two visits to Bramall Lane have ended in 1-1 draws and this one made it a hat-trick.
Former Blades striker Jonathan Forte gave Oldham a deserved lead after below par first half display from the home side.
However, Jamal Campbell-Ryce netted two minutes after coming on as a substitute to earn United a point and it was the Blades applying the late pressure.
Loan defender McCarthy was back after suspension, whilst Baxter was promoted from the bench to face his former club. Reed and Campbell-Ryce dropped to the bench, where they were joined by new capture Adams, named in a Bramall Lane squad for the first time. Visitors Oldham included three former Blades -Philliskirk and Forte started, whilst Poleon was amongst the away substitutes.
It took United just 23 seconds to create the first chance, Flynn's pull-back saw Baxter turn and shoot but Rachubka pushed the ball around a post, whilst the result corner saw Alcock win the initial header but the Blades were unable to capitalise.
Oldham's first opportunities were centred around Ibehre. His shot from a Mills cross was at Howard and a moment later he got the better of McEveley and Harris but the subsequent cross was cleared.
In a build-up similar to his goal at Doncaster seven days earlier, Murphy cut in from the left but this time his shot was deflected wide and there was a similar ending to a Harris effort following a neat move which switched from one side of the field to the other.
Basham, back in midfield, headed wide a Baxter corner at the near post and Doyle picked up the first booking of the game, preventing Forte from breaking away. However, moments later Oldham did get behind the Blades defence and the result was a goal. Johnson's dink found FORTE, who held off McEveley and slid home past Howard.
Before and after the goal, Oldham did well to nullify United's threat with a well-organised system and the next chance could have extended the visiting side's lead but Johnson curled over after Alcock could only half-clear a cross.
As the half progressed, Oldham continued to prove to be difficult to break down. Scougall fired from distance after a move on the right and Harris, first time, smashed a daisy cutter which Rachubka almost pushed into the path of Basham.
Another quick free-kick close to the break almost presented Oldham with another chance but the half-time whistle, soon after, gave United the opportunity to regroup after a testing first period.
Early in the second half Baxter curled a free-kick over and Flynn and Harris both picked up bookings. Oldham's organisation kept United at bay and Basham's shot from distance was over. At the other end Johnson's free-kick came off the wall and Ibehre hit the side-netting.
Campbell-Ryce replaced Baxter just after the hour and it took just two minutes for the change to be effective. Oldham could only half-clear a Harris cross and when the ball dropped to CAMPBELL-RYCE he took a touch out of his feet to gain a yard and his low shot may have taken a slight deflection off the studs of Mills before finding the bottom corner.
With the game in the balance, the later stages were a nervous affair with half-chances at both ends. For United, Basham fired at Rachubka, with his left-foot, and Campbell-Ryce cut in from the left and his deflected effort was clipped over the crossbar by the goalkeeper. For Oldham, McEveley was crucial in preventing Forte connecting with Johnson's pass and Mills fired wide.
As the game entered the final 10 minutes, Murphy turned the ball over after Flynn delivered Campbell-Ryce's cross back into the danger area at the Kop end. Then Oldham finished the game with ten men when Ibehre's altercation with Flynn earned him a second yellow card.
The Oldham fans wanted a red card for McEveley after pulling back Poleon but yellow was the decision. From the resulting free-kick Dieng headed wide at the back post.
Five added minutes was signalled and United applied the pressure but an offside flag and a header over the crossbar was all that was to show for the late efforts ahead of the final whistle.
Blades: Howard, Alcock, Harris, Basham, Flynn, Doyle, Murphy, Scougall, Baxter (Campbell-Ryce 61), McEveley, McCarthy.
Unused: McGahey, Reed, De Girolamo, Turner, Kennedy, Adams.
Oldham: Rachubka, Mills, Dieng, Kelly, Jones, Philliskirk, Forte, Johnson (Poleon 80), Wilson, Ibehre, Kusunga.
Unused: Dayton, Mellor, Winchester, Tidser, Lockwood, Etheridge.