Wigan went into the break a goal down courtesy of a tap in from Florent Malouda after Chris Kirkland had superbly saved a Frank Lampard effort.
After the break, two quick goals from Nicolas Anelka sealed a win that was underlined in the final 11 minutes with a brace from Salomon Kalou and one for Yossi Benayoun.
"We have started well this season, scoring a lot of goals, playing good football," said Chelsea boss Ancelotti.
"But the first half was tough. Wigan played good football, put pressure on us, and we were not able to play our football as there was no space.
"But we defended well, didn't give them opportunities and we waited to score, which is important because in football you have to defend and attack.
"It's impossible to have total control of the game with possession, sometimes you have to defend, and in the first half we defended very well.
"Maybe they spent a lot of energy in the first half because in the second it was easier for us as we had more opportunities to score."