Three goals either side of half-time, included a first-half hat-trick from Nicky Maynard meant the Stags recorded a comfortable victory that didn’t tell the full story overall of the afternoon.
Head Coach Dino Maamria brought back Gary Woods in goal after his groin injury and gave Urko Vera his first start and appearance in attack of his tenure.
But the opening half, and ultimately the game, at Field Mill would turn out to be a rollercoaster of emotions for both sides.
The hosts who were sitting two places and two points above Latics before kick-off started the brighter with Danny Rose, who was the joint top scorer in the league with seven before the fixture, having a handful of chances that were stopped by Woods.
But as Latics battled back the game took a turn on the half-hour mark when the Stags took the lead through Nicky Maynard.
The frontman headed in from close range unmarked after a pin-point cross found the former Bury FC attacker from the right.
A couple of minutes later and Maynard doubled his and the Yellows lead as he tapped in with it being inches from the line as Otis Khan drove forward and played the ball across from the left at the byline.
Things would go from bad to worse when Tomas Egert and Filipe Morais received their marching orders on the 36th minute.
Egert was given a straight red for a strong diving challenge before Morais got his second bookable offence after an altercation with referee Lee Swabey.
A change was made instantly by Latics to sure up the gap in defence as Urko Vera made way for Jamie Stott.
Oldham would seemingly play better with nine men as Hamer pulled an unlikely goal back just before the interval.
The youngster powering home the ball into the net inside the box after finding himself unmarked with the cross drifting in the from the wing.
John Dempster’s side would come forward again though and it was Nicky Maynard who put the home side back in cruise control.
Rounding Gary Woods before slotting the ball in the goal from an angle to complete his hat-trick in first-half stoppage time to bring to an end a frantic opening 45.
The second period had a similar feel as Oldham were totally against the odds. Maamria’s side showed some fight early on to keep the score down but Mansfield got their fourth on the 55th minute as Wheater’s wicked deflection from a Benning cross caught Woods off balance to further compound the disappointment and hurt.
As both sides made changes for differing reasons with former on-loan striker Dapo Afolayan coming on for the hosts and netting the fifth just after the hour mark.
Mansfield countering with speed through Maynard who found Afolayan who duly accepted the offer of sliding the ball home despite being under pressure.
In the process young Dylan Fage who came on only five minutes before the incident fell awkwardly trying to recover. Receiving lengthy treatment on the pitch the French midfielder was stretchered off in a brace to make the afternoon even worse.
As Mansfield Town kept coming forward, the Latics faithful continued to make noise but the sixth and final goal from the hosts came in the final ten minutes.
Hamer challenging Afolayan in the box, the referee awarded the home side with a penalty with youngster Knowles converting it comfortably sending Woods the wrong way.
As nine minutes of stoppage was shown Oldham prevented any further goals for what will be a disappointing performance for a number of reasons; with the playing staff acknowledging the response from the travelling fans who never stopped supporting the side all day despite the circumstances that unfolded.
Mansfield Town: Logan, Benning, Pearce (C), Bishop, MacDonald (60’ Afolayan), Khan, Maynard (68’ Knowles), Shaughnessy, Sweeney, Gordon, Rose (54’ Cook).
Oldham Athletic: Woods, Iacovitti, Morais, Vera (38’ Stott), Maouche (61’ Fage – 73’ Smith-Brown), Missilou, Sylla, Smith, Egert, Wheater (C), Hamer.
Attendance: 4,368 (441 Latics)
Referee: Lee Swabey