Londoners blow early lead as Latics fight back to earn an important point at home to emerge from out of the league's relegation zone
Daniel Sturridge was lively throughout and his single moment of class on the hour-mark seemed more than Wigan could reply to, but a late howler from Chelsea keeper Peter Cech gave the Latics their desperately needed lifeline.
The match began with each side feeling the other out, Chelsea being only marginally more probing. It took 15 minutes for a Blues player to threaten the Wigan net, but John Terry's driven shot fired wide from 25 yards.
The first shot on target wasn't registered until the 22 minute mark. Jose Boswinga curled in a cross from the right-side, the rebound finding its way firmly onto midfielder Oriol Romeu's right-foot but his volley from 22 yards was excellently saved by a diving Ali Al Habsi.
The hosts had a dubious penalty shout on the 41-minute mark. Branislav Ivanovic seemed to block a Victor Moses shot with his arm, but referee Martin Atkinson waved off appeals.
Replays confirmed the Serbian had drawn his hands into his body before blocking the shot, arguably justifying the official's inaction.
At the interval, Chelsea manager Andre Villas-Boas made the first switch of the league's two youngest managers. Saloman Kalou entered at the expense of Romeu.
The first half-chance of the frame came when Kalou worked his way around Wigan left-back Antolin Alcaraz after 55 minutes, feeding Drogba whose stabbed shot was just wide Al Habsi's inside post.
Moments later, the deadlock between the two sides was mercifully broken. Ashley Cole was afforded space to edge into Wigan's half and pick out his pass. He crossed long and through for a running Daniel Sturridge.
The younger Englishman's first touch was true, setting up a punishing second that smashed the ball at a sharp angle past the Wigan keeper to give Chelsea the 1-0 lead on 59 minutes.
Latics manager Roberto Martinez finally showed his hand on 72 minutes, introducing perennial match-winner Franco di Santo for forward Connor Sammon and Hugo Rodallega for the left back Jones.
The Londoners were closing out the tie by defending deeply against relatively tepid attacks from their single-minded hosts, but on 88 minutes Cech fumbled a tame toe-poke from Rodellaga and Jordi Gomez plundered to equalize 1-1.
With the draw, Chelsea (32) trails second place Manchester United (36) by four points, a further two behind league leaders Manchester City (38). Wigan, meanwhile, climbs out of the relegation zone with 15 points.