Kal Naismith was red-carded after 15 minutes as Wigan Athletic suffered only their second defeat of the campaign thanks to Jack Marriott’s first-half goal for Derby County.
Latics had started well, creating a golden opportunity that James Vaughan came agonisingly close to converting, before Naismith was dismissed for a last-man foul on Harry Wilson.
The Rams took the lead within five minutes through Marriott’s predatory header, and only a goalline clearance from Nathan Byrne prevented Wilson making it 2-0 shortly after.
Latics boss Paul Cook took drastic action to stem the bleeding, withdrawing Vaughan and Gary Roberts with only half an hour gone, and sending on Callum Connolly and Darron Gibson as well as switching to a 5-3-1 formation.
After that, the home side arguably edged the encounter, despite being a man light, but couldn’t force former Latics goalkeeper Scott Carson into much meaningful action.
Latics will argue the bounce of the ball didn’t go their way, with Derby starlet Wilson being cautioned in the first half for an altercation with Morsy, before appearing to throw himself to the ground in the second stanza in an attempt to win a penalty, only for referee Gavin Ward to give him the benefit of the doubt.
But there was plenty in the way of positives for Cook and Latics to cling to, with the buffer to the bottom three remaining a healthy seven points.
And it could have been even more had Latics taken advantage of a flying start that saw them carve open Derby with embarrassing ease.
A lovely passing move involving Naismith, Morsy and Josh Windass led to Gary Roberts sending over a teasing cross that Vaughan couldn’t quite get on the end of.
And Derby, who’d seen Jayden Bogle force Christian Walton into an early stop, went on to take full advantage.
Wales international Wilson was played in on goal before being tugged back by Naismith, who knew straight away there was only one decision the official could make.
As Latics tried to reorganise at the back, they were rocked by the Rams taking the lead on 20 minutes.
Bogle was left in acres of space down the right wing, and his pinpoint cross was headed home well by Marriott.
Only an acrobatic intervention from Byrne on the Latics goalline prevented Wilson doubling the lead, before Latics made a double change - and a formation tweak - to try and stay in the game.
Derby remained on top, however, with Tom Lawrence firing just over and Walton doing well to keep out a Mason Mount strike.
Wilson was causing Latics plenty of problems, and he took exception to one challenge from Morsy that brought both players together, head-to-head.
With the Wigan captain claiming he’d been headbutted, the official elected to diffuse the situation by dishing out a brace of yellow cards,
When the football broke back out, Reece James sent a free-kick straight at Scott Carson just before half-time.
Latics came out for the second half with renewed gusto, and a fine cross from the left by Byrne deserved somebody to be on the end of it.
Morsy and Windass then created an opening for James, who will perhaps feel he might have done better than steer his shot into the arms of a grateful Carson.
Tempers were frayed again when Wilson went down in the box under little or no contact from Dan Burn, who clearly felt his opponents had tried to win a penalty from the official.
Having somehow escaped a second booking, which most of the Latics players and supporters were baying for, it was no surprise to see Wilson hooked at the next break in play.
Unfortunately Latics weren’t able to take advantage of decent pressure, and the introduction off the bench of Joe Garner, to eke out an equalising goal.