
Petr Cech saw red in an explosive start to the second-half which saw Chelsea equalise before immediately conceding a penalty, which Hugo Rodallega won and dispatched.
Chelsea had won each of their six games so far this season and only this week were being labelled as almost unbeatable, a tag which manager Carlos Ancelotti rebuffed.
Titus Bramble opened the scoring on 16 minutes when he headed home unmarked from around 8 yards when Charles N'Zogbia delivered after a short corner.
The Latics held on until half-time and perhaps should have taken advantage of some suspect Chelsea defending as Emmerson Boyce shot straight at Cech from inside the six yard box.
Chelsea began the second-half in great urgency and were level on 47 minutes as Didier Drogba steered home Florent Malouda cross past Chris Kirkland in the Wigan goal, who was guilty of failing to hold the Ivorian's tame effort.
Wigan were back in front soon after when Cech brought down Rodallega inside the after the Columbian raced through on goal.
Florent Malouda was sacrificed as Henrique Hilario came in to replace Cech in the Chelsea goal but he was sent the wrong way by Rodallega, who picked himself up to drill home the penalty.
Chelsea were unable to regain control of the game as play resumed and after using all three subs, they were reduced to nine men after Ashley Cole was unable to continue in injury time.
The away side were massively exposed as they desperately searched an equaliser and Paul Scharner capitalised when he poked home from a yard out after great wing play by Maynor Figueroa a minute into added time.
So, another disgraceful display of refereeing. When are prats like Phil Dowd going to realise that the fans come to see eleven men against eleven, not the likes of him.
Make no mistake, if Cech had been wearing a Man. Utd., Liverpool or Arsenal shirt in the same situation he would have stayed on the pitch.
Still, we'll win the league despite the officials, not because of them. We always have before.