In-form striker Andy Liddell put Wigan in front five minutes before half-time when he fired home from the penalty spot for his sixth of the season.
Front line partner Nathan Ellington doubled the lead just after the interval but Posh defender Adam Newton set up a tense closing half-hour by grabbing a goal back for the visitors.
Experienced striker Andy Clarke then hauled Posh level on 76 minutes to nick a valuable point for Barry Fry's outfit and halt Wigan's early promotion charge.
Previously second placed Queens Park Rangers crushed Bristol City's 100 percent record at Ashton Gate despite falling behind to Scott Murray's fifth of the campaign after 11 points.
R's boss Ian Holloway had never previously won in Bristol as a visiting manager but a goal in each half from Karl Connolly and a third from Kevin Gallen ensured he departed his home city with a smile on his face.
Oldham had to battle for the points at Layer Road after being reduced to ten men with the sending off of Clint Hill. But Colchester's Mark Warren was then dismissed for violent conduct before Wayne Andrews snatched a winner for the visitors on 64 minutes.
Big-spending Cardiff maintained their formidable away record courtesy of Gary Croft's first goal for the club on 20 minutes at Notts County.
Crewe keep apace with the leaders after a comfortable home triumph over Tranmere. Tom Curtis put into his own net on 57 minutes and Rob Hulse extended the host's lead on 73 minutes.
Play-off hopefuls Blackpool and Port Vale were involved in a thrilling tussle at Bloomfield Road as the lead swung like a pendulum.
Sam Collins put Vale ahead on 23 minutes only for a quick-fire double from John Murphy in the second half to forge Blackpool in front.
Port Vale levelled through Marc Bridge-Wilkinson on 71 minutes but inside the closing ten minutes, Peter Clarke edged The Seasiders ahead again.
Brentford were pushed all the way by Wycombe but Stephen Hunt's 57th minute penalty sent the Griffin Park crowd into raptures.
Plymouth's perfect record at Home Park was dented by Chesterfield, who nicked the points through Marcus Ebdon's 69th minute winner.
Stockport produced a devastating second half display to hammer Barnsley, who had the temerity to take a first half lead through Rory Fallon.
But after the interval both Jim Goodwin and the prolific Luke Beckett helped themselves to a brace apiece.
Struggling Swindon received the ideal fillip with a 2-0 home success over ten-man Northampton.
Johnnie Jackson fired The Robins ahead on 31 minutes and Sam Parkin secured the win on 79 minutes from the penalty spot after The Cobblers had goalkeeper Lee Harper sent off for a professional foul.
Cheltenham earned their first away win of the season and nipped Mansfield's mini-revival in the bud in the process at Field Mill.
Jamie Victory sent Cheltenham on their way on 71 minutes and Hugh McAuley alleviated fears of a nervous finale with the second on 84 minutes.
Luton boosted their morale with a late, late show at the McAlpine Stadium as Steven Howard snared an injury time winner against Huddersfield.
Click on the links below for an individual match summary:
Blackpool 3-2 Port Vale
Brentford 1-0 Wycombe Wanderers
Bristol City 1-3 Queens Park Rangers
Colchester 0-1 Oldham
Crewe 2-0 Tranmere
Huddersfield 0-1 Luton Town
Mansfield 0-2 Cheltenham Town
Notts County 0-1 Cardiff City
Plymouth 0-1 Chesterfield
Stockport 4-1 Barnsley
Swindon 2-0 Northampton
Wigan 2-2 Peterborough
