The FA Cup holders began their 2014 competition with a six goal thriller at the DW Stadium as MK Dons fought back twice to force a replay.
Roger Espinoza's thumping effort gave Latics the lead, before Jordi Gomez doubled it ahead of the half hour mark. MK Dons had other ideas though, with Ben Reeves scoring twice in the final two minutes to level at 2-2.
The drama in this good, old-fashioned cup tie continued when Ali Al Habsi saved a penalty from Shaun Williams five minutes before Callum McManaman made it 3-2, but with eight minutes remaining a goal in his last game for the club for Patrick Bamford forced a third round replay.
Uwe Rosler fielded a strong side in Latics' first FA Cup tie since the final, but made four changes from the previous league game against Derby County, with Grant Holt, James McClean, Callum McManaman and Jordi Gomez all coming in to start.
It was the perfect start to the defence of the FA Cup, lots of early pressure and eventually a goal on 18 minutes when Roger Espinoza fired in his second goal for the club.
The Honduran international's first strike for Latics last season against Swansea City was a special effort, but he went one better with his one, pushing the ball out of his feet from and angle on the left edge of the area and hammering the ball into the top right corner, with MK Dons 'keeper David Martin helpless to stop it.
Flowing football continued as the first half progressed, with James McClean's direct style earning countless corner as he ran the game down the left wing.
On 26 minutes Latics' pressure paid off again, this time with Jordi Gomez getting his name on the score sheet for the fourth time in his last eight FA Cup appearances.
MK Dons couldn't clear down their left side, and cutting in from the right side of the area, Gomez simply slotted the ball near post underneath Martin to send the DW into a frenzy once more.
After a dominant spell of possession at the start of the half for Latics, MK Dons began to get in their groove.
Shots were fired high and wide for a while, but pressure mounted from corner kicks until Latics had the perfect chance to make it 3-0 on 41 minutes.
From an MK Dons corner, Callum McManaman countered down the left wing with McClean in support in the centre, but a low ball into the area was cut out inches from the Republic of Ireland internationals foot.
As the first half drew to a close, MK Dons made Latics pay for their missed chance, first with Ben Reeves popping up from nowhere to sweep the ball home from close range on 45 minutes, before following it up with another close range finish in the final minute of added time.
The visitors came out strongly in the second half after their late first half revival, with Dele Alli forcing Ali Al Habsi into a low save from range.
Continued pressure paid off for Karl Robinson's men on the hour mark when they were awarded a penalty kick for a high arm by McClean on George Baldock as he entered the area, the call a debatable one as to whether Baldock had entered the box.
Up stepped Shaun Williams, seven penalties scored from seven so far this season, but he didn't bank on Latics' penalty saving expert Al Habsi who sprung from his line to beat the ball away as the score remained 2-2.
Things got even better for Latics on 65 minutes, when opening scorer Espinoza chipped the ball over the defence into the path of McManaman who slotted the ball into the bottom left corner one-on-one with David Martin.
McManaman's sixth goal in his FA Cup career looked like it could have been the tipping point for MK Dons.
Substitute Marc-Antoine Fortune had a golden opportunity to give Latics a second two-goal lead of the afternoon when he was picked out expertly by Espinoza with another chip over the defence, but the striker's run on goal ended with a dragged shot well wide.
An upset could be sensed by the near 1,000 travelling Dons fans, and on 82 minutes Patrick Bamford (playing his last game for the club before his loan move to Derby County) made Latics pay for not clearing a corner as he slotted the ball through bodies in a goal mouth scramble.
With eight minutes to play plus five minutes of stoppage time both sides looked desperate to avoid a replay, but neither could score a fourth.
Uwe Rosler's Latics will now travel to StadiumMK on 14 January, as they begin the 2014 FA Cup in the same manner as 2013, with a draw at home.