Ramires and Eden Hazard gave the Blues a 2-0 lead which Shaun Maloney halved after 58 minutes, before Lampard's 86th-minute strike saw him move to within four of Bobby Tambling's club goalscoring record of 202.
Substitute Marko Marin added a stoppage-time fourth as Chelsea, who had won just three of the previous 10 games, triumphed for the first time since the defeat of Arsenal.
"We deserved to win," Benitez said.
"To win is something you have to do. Top sides, if you want to win something, you have to be consistent winning. It's normal.
"But it's not the end of the world if you draw a game you deserve to win.
"The problem for me would be if we don't create chances; we create chances every game.
"We score goals. We're making some mistakes, but we have a lot of positives. Today [Saturday] four goals could be six goals at the end."
Benitez has finally accumulated more Premier League points than his predecessor, Roberto Di Matteo, whom he replaced in November - albeit in two more games.
It is a result which is likely to at least delay Chelsea owner Roman Abramovich, who is not renowned for his patience, reaching for the trigger. Benitez was unfazed.
"It was just speculation," he said.
"Nobody is in contact with the owner to find out if he says this or that. It is my job: try to win every game. That's it, so I have to concentrate on that."
Chelsea again were reliant on Lampard, who scored the decisive goal for England against Brazil in midweek.
The future of the 34-year-old is unclear, with contradictory speculation in midweek over whether the midfielder will be offered an new contract to extend his 12-year stay beyond this summer.
Benitez said: "The last two months he's scored eight or nine goals - really pleased.
"If he scores 20 goals and breaks the record, I'll be really pleased."
Benitez would not be drawn on Lampard's future when asked how long the midfielder can continue to play at the highest level, referring only to next week's Europa League clash with Sparta Prague.
"If he's available for Thursday, I will be really pleased," the Spaniard said.
Benitez believes the returns of Hazard and David Luiz aided Chelsea, even in the absence of captain John Terry, who has a knee injury. He had more options with which to work.
"In the past we didn't have these kind of options and it was more difficult to change the game," Benitez said.
"It will be important for us to have more bodies and manage the games, change players and with the quality we have it will be easier."
There was a moment of alarm when, with Chelsea leading 2-1, the visitors had a penalty appeal declined after Ronnie Stam's shot struck Ashley Cole on the arm.
"I couldn't see," Benitez said.
Wigan boss Roberto Martinez reckons officials should be given further guidance for such incidents.
"The referees need a bit of clarity," Martinez said.
"I tell my defenders not to put themselves in a position where it could be a penalty.
"The defender should have had his arm 'attached' to his body. Clearly the arm wasn't.
"But it's down to the interpretation of the referee. It's a difficult call."
Martinez was happy with his side's display and believes the final scoreline was down to their bid to claim an equaliser.
"I had to stretch the game, open up and leave ourselves exposed and on the counter-attack Chelsea took advantage of that," he said.
"We were long enough in Chelsea's defensive third, and we had that presence there.
"I did feel that, if we'd got the equaliser, the ending would have been very interesting."