Matt Taylor scored with a 25-yard free kick after U.S. defender Oguchi Onyewu fouled Leighton Baines in the 40th minute. Twelve minutes earlier, Wigan goalkeeper John Filan saved a penalty kick by Nolberto Solano.
The victory put Wigan at least six points ahead of the three teams in the relegation zone. Wigan has 29 points while Charlton has 23, West Ham has 20 and Watford has 19.
MILAN, Italy (AP) _ Inter Milan won its 17th straight game in the Italian league, defeating Catania 5-2.
Walter Samuel, Santiago Solari, Fabio Grosso, Zlatan Ibrahimovic and Julio Ricardo Cruz scored for Inter, which leads the league with 66 points. Gionatha Spinesi and Giorgio Corona scored for Catania.
Second-place AS Roma downed Reggina 3-0 and has 52 points. Palermo, which tied Atalanta 1-1, is third with 44 points.
AMSTERDAM, Netherlands (AP) _ Ajax was held to a 1-1 tie by AZ Alkmaar in the Dutch league.
Kenneth Perez gave Ajax the lead in the 65th minute, but AZ substitute Maarten Martens tied the score in the 79th. Ajax played half the game with 10 men because Edgar Davids was sent off in the 45th minute for a second yellow card.
Ajax is still in second place with 56 points, seven points behind PSV Eindhoven, which beat FC Groningen 1-0 Saturday. AZ is third with 55 points.
GLASGOW, Scotland (AP) _ Celtic advanced to the semifinals of the Scottish Cup by edging Inverness Caledonian Thistle 2-1 on a pair of late goals.
Steven Pressley scored in the 89th minute and Kenny Miller added another during injury time for the 33-time cup champions. Inverness had taken the lead in the 18th when Graham Bayne scored.
Dunfermline and Hibernian are also in the semifinals. Motherwell faces St. Johnstone on Wednesday.