GOAL machine Jordi Gomez notched his fourth goal in five games as Latics deservedly grabbed a share of the spoils against the high-flying Blues.
Chelsea had led through their first real shot on goal on the hour mark, Daniel Sturridge controlling superbly and firing in an unstoppable shot past Ali Al Habsi.
But Latics never gave up hope and, after several near-misses - not to mention a couple of decent penalty shouts that went unheard - they got back on level terms in the most dramatic fashion.
With time running out, Petr Cech couldn’t hold substitute Hugo Rodallega’s effort, and Gomez steered the ball home from close range to the delight of the home supporters behind the goal.
The result gives Latics a near-perfect start to their gruelling festive programme, and sends them into Wednesday’s clash with Liverpool in good spirits.
Antolin Alcaraz had given Latics a massive pre-match boost by passing a late fitness test on the rib injury he picked up at West Brom, meaning the side were unchanged.
Chelsea boss Andre Villas-Boas made one change, Frank Lampard for Ramires as the Blues went for a fourth win on the trot.
Having won 6-0 in the corresponding fixture last term, Chelsea were red-hot favourites coming in to the game.
But the home side settled by far the quicker, and Cech almost carried the ball out of his penalty area whilst defusing Wigan’s first attack.
There were calls for a home penalty on the five-minute mark when Gomez went to ground in the Chelsea box, but referee Martin Atkinson ruled otherwise.
Sturridge created the first bit of Chelsea danger, skinning David Jones down the right and putting in a teasing cross that was well dealt with by Gary Caldwell.
The skipper then had to do likewise from an Ashley Cole cross from the other side as Chelsea pressed for the opener.
With the visitors enjoying more and more of the ball, Al Habsi was forced to make his first real save midway through the half.
A Didier Drogba cross was half-cleared to Oriol Romeu 25 yards from goal, and Al Habsi was at full-strength to turn the volley past the post.
The shot was perhaps missing by a yard in any case, but the goalkeeper was taking no chances and the resulting set-piece was easily cleared.
A superb passing move then saw Latics turn defence into attack in style, although the final ball from Ronnie Stam was cut out by the defence.
One swift lump up the field saw Chelsea threaten on the counter, although Raul Meireles was stopped dead in his tracks by a perfectly-timed sliding challenge by James McCarthy.
The Republic of Ireland midfielder then showed his prowess at the other end with a nice ball to play in Victor Moses after Conor Sammon had done well to turn John Terry down the left channel.
Chelsea managed to clear the danger but the respite was only temporary, Momo Diame receiving the ball out left and cutting inside before drilling in a right-footed shot that only just flew past the far post.
A section of the home fans, however, showed what they thought of Wigan’s efforts with a standing ovation, and Wigan were nearly in again when some lovely interplay from Jones and Diame saw Moses isolated against Branislav Ivanovic.
Moses sent the ball past the defender and went in hot pursuit before being blocked off by Ivanovic, referee Atkinson again waving play on.
Despite being increasingly on the back foot, Chelsea showed they were still a threat when Jose Bosingwa’s cross was nodded inches wide by Drogba.
But back came Latics and they were denied a penalty for the second time three minutes before the interval.
Jones’ cross was deflected away by Terry to Moses just inside the box, and the winger’s snapshot was arrowing goalwards before being blocked by the forearm of Ivanovic.
With three-quarters of the DW Stadtionium screaming for handball, Atkinson was again unmoved - much to the disgust of those in blue.
And there was more frustration on the stroke of half-time when Sammon released Jones down the left, and his cross was only just in front of an onrushing Moses who would have had a tap-in.
Chelsea made an attacking change at the break, Salomon Kalou for Romeu, and the Ivorian was quickly into the game, winning a corner off Stam.
And Caldwell had to move smartly to make a vital interception to nick the ball away from Drogba to halt the Blues’ next foray.
Latics flexed their offensive muscles six minutes after the restart, and it almost brought about the first goal.
Diame’s cross was only just too high for Sammon although Bosingwa made a mess of a routine clerarance.
The ball looped to Moses, who juggled the ball left and right deep inside the penalty area, before smashing a volley wildly into the winter air as opposed to the roof of the net.
Lampard was forced off the field just before the hour mark for some running repairs after colliding with Diame’s elbow, but the visitors overcame the temporary one-man disadvantage to score during his absence.
There seemed little danger as Cole’s long ball found Sturridge inside the area, but well wide of the goal.
If the control was excellent, the finish was even better, Al Habsi hardly seeing the ball flash across his body on its way into the bottom left-hand corner.
Latics attempted an immediate response and, although Jones’ shot was well wide of Cech’s goal, their next effort on goal forced a great save from the Czech goalkeeper.
Maynor Figueroa was invited to run some 60 yards with the ball, and his shot was bound for the bottom corner before Cech’s left hand diverted it round the post.
Roberto Martinez made a double change with 18 minutes left, Jones and Sammon off and Franco di Santo and Rodallega entering the fray.
Di Santo made his presence felt right from the off, competing for a ball with Terry in a collision that saw the England defender come off second best by a mile.
And both subs almost combined to fashion an equaliser from Wigan’s next attack.
A poorly-weighted backpass from Ivanovic was always going to struggle to reach Cech, and Rodallega was on to it like a flash.
Credit to Cech, he managed to get a block on the ball as Rodallega tried to push it past him, only for Gomez to send it back into the danger area with the Chelsea custodian still on the deck.
The ball found its way to Di Santo, with his back to goal, and his shot on the turn was going in before it was sent off course by the head of Terry and behind for a corner.
It was all Latics by this point, the visitors happy to hang on for the 1-0 victory despite its precarious nature.
And the home side’s pressure was finally rewarded with two minutes remaining when Cech could only parry Rodallega’s rather weak stab towards goal, but Gomez was on hand to finish from inside the six-yard box.
Rather than sit back on their laurels, Latics continued to press into the four minutes of stoppage time, and Di Santo’s header from Stam’s cross was only just wide of the mark.
Di Santo got his header from another Stam’s cross moments later, but the Argentine had fouled his man and Chelsea were able to clear their lines.
A cheap free-kick on halfway saw the visitors launch an attack, only for Stam’s big boot forward to set up a three-on-two Latics break.
Moses helped the ball on to Di Santo on the edge of the area, and the striker was bundled off it by the last defender - only for Atkinson to again wave play on.
Latics: Al Habsi 7; Alcaraz 8, Caldwell 8, Figueroa 7; Stam 8, Diame 8, McCarthy 8, Jones 8; Moses 8, Gomez 8; Sammon 7.
Subs: Pollitt, Gohouri, McArthur, Watson, Crusat, Di Santo (for Sammon, 73) 7, Rodallega (for Jones, 73) 7.
Chelsea: Cech; Bosingwa, Ivanovic, Terry, Cole; Lampard, Romeu, Meireles; Sturridge, Drogba, Mata.
Subs: Turnbull, Ferreira, McEachran, Mikel (for Mata, 66), Malouda (for Sturridge, 79), Kalou (for Romeu, 46), Torres.