The midfielder coolly slotted home a reverse pass from Dave Kitson in the final moments to hand the Royals only their second win of the league season.
Reading didn't play like a team with just one win to their name this season and the home side looked hungry from the off.
Liam Rosenior had the chance to mark his home debut with a goal midway through the first half when Kevin Doyle's flicked header left him in the clear, but the defender's snap-shot was beaten away by an alert Chris Kirkland.
But Kirkland then made a mess of a Kevin Doyle shot to gift Kitson the opener on 29 minutes.
Doyle, back in the starting line-up at the expense of Leroy Lita, turned well in the box and hit a low drive that Kirkland stopped but could not hold, allowing Kitson to pounce and poke home.
It was Kitson's second goal in just two starts this season and justified the inclusion of him and Doyle ahead of Lita.
But Wigan were nearly handed an immediate lifeline when the rampaging Jason Koumas was clipped on the edge of the box by Ivar Ingimarsson.
Referee Keith Stroud initially appeared to point to the penalty spot but, after consulting with his assistant, awarded only a free-kick.
It didn't seem to make much difference to Koumas though, as his superb strike beat Marcus Hahnemann but cannoned off the underside of the bar and down on the goal-line before being scrambled clear.
But the visitors were back on level terms within five minutes of the second half when Marcus Bent celebrated his first league start for Wigan with his first goal for the club.
Ingimarsson conceded a corner and Koumas' pinpoint centre allowed Bent to get between Kitson and Michael Duberry to power a header past Hahnemann.
Ten minutes later he nearly had a second when he sprinted clear on to a quickly taken throw and stung the hands of Hahnemann with a low snap-shot.
The near miss seemed to spur the home side on and they gradually increased the pressure in search of their first win in more than a month.
Stephen Hunt flicked a header wide and Doyle shot straight at Kirkland, before Kitson came within inches of scoring when he fed substitute Bobby Convey and raced to get on the end of the winger's low cross, only to narrowly fail to reach the centre in front of an empty net.