They are just four points behind City and 11 adrift of leaders United, with a match in hand of both.
Benitez accepts confidence is high at Stamford Bridge but has told the players to focus on their next match, at home to struggling QPR.
"We have one game in hand but still we have to win this game," Benitez said. "Our idea is to think about one game at a time. We will see where we are after some games.
"I was really pleased with the Everton win because you could see the character of the players."
Benitez would not comment on Lampard's future, with speculation suggesting he will not be offered a new contract when his current deal expires at the end of the season.
He also sidestepped claims Chelsea had opened talks over signing Newcastle's Demba Ba.
"Lampard is a great player, a good professional, who is doing well for us and I will try to bring the best out of him until the end of the season," Benitez added.
"He is one of the players who if he gets in the box he can be dangerous. He is under contract. He has shown his full commitment. He is a great player and my job is to keep him fit, happy and scoring goals.
"If he can score goals every game I'll be pleased."
On Ba, Benitez merely said: "We don't talk about our business in public. My job is to prepare for the games, enjoy them if we win and then after they (the club) will let me know what is going to happen.
"He is a player who is playing for another team so I don't like to talk about other players."
Despite the disappointment of seeing their 13-match unbeaten league home record ended, Everton manager David Moyes remained upbeat.
His side finished 2012 with their biggest points tally in a calendar year since 1987 and their highest number of Premier League goals in 12 months, with Pienaar's strike beating the previous best of 64 in 1996.
Moyes said: "2012 has been a good year for us. There is nothing we can look back on and say we have done too much wrong.
"We're not disappointed with the way we've played because we played really well and we've run the European champions close, but we didn't quite have enough in the end.
"I thought we were a bit unlucky. We tried to make what we had work the best we could and for long periods I thought we did, we played well enough to get something from the game. We were limited with what we had, not having Phil Neville and Darron Gibson (through injury) and not having Marouane (Fellaini) because of suspension.
"Darron has a thigh strain which will keep him out for a while so we're short and we know that."