So much for a procession towards title number 20. Before kickoff the talk at the ground was of how, with an unlikely sequence of results, Manchester United could seal their latest league crown on Sunday. By Phil Dowd's final whistle, with Phil Jones deployed as an emergency centre-forward with a short fuse, Wayne Rooney stewing on the bench and the Wigan chairman Dave Whelan conducting an impromptu radio interview in the press box, football's chaos theory had prevailed once more. Two Robertos, Martínez and Mancini, had renewed hope.

This was a wobble where and when United least expected it. Sir Alex Ferguson had previously faced Wigan 14 times since their elevation to the Premier League and 14 times he had emerged victorious. The sequence came to an abrupt halt as United foundered in the face of a superb Wigan display and then, as Athletic sought to protect the lead given to them through Shaun Maloney's exquisite goal, rarely threatened another stirring late recovery.

The league leaders did have a clear penalty rejected when Maynor Figueroa handled Jones's cross with 18 minutes remaining, and they could dispute the corner that led to Wigan's winner. Tellingly, not even Ferguson railed that hard. His side were deservedly beaten for the first time in 13 league matches, a sequence stretching back to Newcastle United on 4 January, and have only themselves to blame for offering Manchester City a lifeline. The rested Paul Scholes was sorely missed in a lethargic performance.

Wigan, in contrast, were excellent in every department. They certainly did not resemble a team stranded in the bottom three before kick-off, sulking over their unjust defeat at Chelsea on Saturday and forced to deny reports that their manager will be leaving this summer regardless of their fate in the Premier League.

"The rumours are unfounded and I wonder where it is coming from," said Martínez. "There are five teams fighting in the bottom five and sometimes these stories come out to unsettle other clubs. There is nothing in it. I agreed a new deal last summer and it still has two years to run."

Martínez had received an apology from Mike Riley, the general manager of the Professional Game Match Officials, for Dave Bryan's failure to spot that Chelsea's goals were offside in the 2-1 defeat at Stamford Bridge, a reverse that broke a run of four games unbeaten for the Latics. Riley's intentions were well-intentioned but would ultimately be worthless should Wigan go down, and the Spaniard was cursing another controversial call when a merited lead was chalked off after 29 minutes.

The outstanding Victor Moses rose highest to send a powerful header beyond David de Gea from Maloney's corner. The DW erupted Moses slid to his knees in celebration and the annoying music that drowns out every home goal celebration at Wigan began to assault the ear-drums. No one had spotted that the assistant referee David Richardson had raised his flag the moment Moses' header hit the net. Only after several television replays was an apparent cause identified, a slight obstruction by Gary Caldwell on the United goalkeeper on the goalline. Harsh in the extreme. Ryan Giggs was still berating his defenders by the time he realised United had been reprieved. Dowd, jeered before kick-off following his erroneous decision to dismiss Conor Sammon in the fixture at Old Trafford earlier in the season, had a vitriolic reception at half-time.

Few would have disputed the legitimacy of Wigan's lead had the goal stood. But for two incisive passes into the home area, the first from Ryan Giggs to Javier Hernández, the second from Michael Carrick to Giggs, intercepted by Caldwell and Figueroa respectively, United threatened little and were second best throughout. Ferguson stalked his technical area like a wounded lion, rehearsing the dressing-room dressing-down he was to deliver during the interval.

Whatever the United manager said, it did not work, and the watching Glazer brothers will not have been amused. Maloney made a quiet start to life at Wigan following his £850,000 move from Celtic last summer but has been instrumental in the team's recent dramatic improvement.

His third goal in 10 games was worthy of any stage. After exchanging passes with Jean Beausejour at a short corner, the Scot cut inside a half-hearted challenge from Rooney on the edge of the area and curled a wonderful finish beyond De Gea and in off the far post.

There was no reprieve for United on this occasion, although Dowd favoured them again when Jonny Evans scythed down Maloney from behind but escaped his second booking of the night.

Moses almost doubled Wigan's advantage in the closing stages and it was not until the 84th minute that the United substitute Danny Welbeck forced the first save of the night from Ali Al-Habsi.