It had looked all over for the Lactics as Posh went into a two-goal lead, but Hughes led the fightback with a goal in either half.
Most of the incidents came in a pulsating first 45 minutes that produced three goals, two penalties and five bookings. Posh grabbed a 12th minute lead when Aaron McLean's cross from a tight angle on the right deflected off Athletic defender Stefan Stam and flew high over Greg Fleming.
Then the 21-year-old Oldham goalkeeper, making his first full start, was cautioned by referee Iain Williamson for a foul on McLean but partially redeemed himself going full stretch to his right to save the Posh man's 20th minute penalty.
Referee Williamson pointed to the penalty spot again 17 minutes later ruling that Reuben Hazell had pushed Craig Mackail-Smith.
This time the 16-goal Posh marksman took the spot-kick himself and slammed his shot against the foot of Fleming's right-hand post. Fortunately McLean pounced on the rebound to double the advantage.
Oldham, who had lost David Jones after a late challenge for which Posh's Craig Morgan was booked, came into the game with Hughes reacting first in a crowded penalty area after skipper Mark Allott fired the ball in low on 39 minutes.
Posh were thankful for a superb clearance by Gaby Zakuani when Hughes challenged again, but they were punished by the Oldham top scorer who levelled the scores with his 11th goal of the campaign following a 58th minute mistake by Joe Lewis, the Posh keeper pushing a free-kick by Andy Liddell directly into the striker's path.
Oldham had the best chance to pinch all three points when Chris Taylor's shot in added time beat Lewis, but Zakuani cleared with a diving header.