Newcastle are fourth on 19 points after the 25-year-old France midfielder curled home a shot in the 81st minute, his first goal for the club since his move from Lille.
Liverpool's drive for a top-four place stalled when they were held to a 1-1 draw by promoted Norwich City at Anfield, leaving them in fifth place on 15 points.
West Bromwich Albion won 2-1 at Aston Villa, Sunderland won 2-0 at Bolton Wanderers and Wolverhampton Wanderers drew 2-2 with Swansea City.
Although Newcastle were not at their best, they were still too strong for struggling Wigan who went down to a sixth successive league defeat, sliding into last place, equal on five points with Blackburn Rovers.
Newcastle manager Alan Pardew told the BBC: "It was a really good effort by Wigan, they were faster than us at times. It needed a bit of magic and it was a great goal, Yohan's technique was top class."
Liverpool, who hit the woodwork three times at Anfield, could not capitalise after ex-Norwich player Craig Bellamy gave them the lead with the last kick of the first half.
Liverpool dominated for long periods but, apart from that goal, could find no way past Canaries 'keeper John Ruddy who made a series of brilliant saves, including one in the fifth minute of stoppage-time from Luis Suarez.
THUMPING HEADER
Norwich's goal came after an hour when substitute Grant Holt marked his 100th appearance for the club with a thumping header, taking full advantage of poor keeping from Pepe Reina.
Ruddy, who had an oustanding match back on Merseyside where he used to play for Everton, told ESPN: "I'm just delighted with the point. I thought we rode our luck a bit in the first half, but in the second half we were a different animal."
The win left Norwich in seventh place, just three points behind Liverpool.
Wolves scored twice in the last five minutes through Kevin Doyle and Jamie O'Hara to end a run of five successive defeats with a 2-2 draw with Swansea.
"We have played better in the last five games and got nothing," McCarthy said. "We needed a break, and hopefully that is it.
"I'm not sure we are jumping around for joy as it has been a difficult day for us, but when you pick the bones out of it, it's a good point."
Elsewhere in the Midlands there was drama in the derby between Villa and West Brom who came from behind to win in the league at Villa Park for the first time since 1979.
After Darren Bent gave Villa the lead with a 23rd-minute penalty, the match effectively turned when Villa defender Chris Herd was sent off for what looked like an innocuous tussle with West Brom's Jonas Olsson.
Referee Phil Dowd also awarded West Brom a penalty which Chris Brunt blasted wide, but he was more accurate with a corner on the stroke of half-time which was headed in by Olsson.
