England international believes the Red Devils were the favorites to win the title, considering the fact that the visitors were 15 points behind about two months ago
The Blues lock horns with Sir Alex Ferguson's charges on Sunday in a potential title deciding game, as the visitors are only three points behind the league leaders.
Being level on goal difference means that the west London club could take pole position with a victory, but a defeat would see the Red Devils six points ahead with only two games left to go.
"We’re going into the game in great form, but most expected United to have wrapped up the title by now," Lampard said, according to The Mirror.
"You won’t see us complaining though. Our main aim at the start of the campaign was to retain the title, despite all the talk about prioritising the Champions League.
"We’re not going to United under massive pressure, only the pressure we put ourselves under. The real pressure is on United because it was their title to throw away."
About two months ago, Carlo Ancelotti's charges were 15 points behind United, and there had been speculation whether the Italian boss would retain his job at the end of the season.
"I’m no different. If you said we would still be in the title race with three games remaining, we would have taken that considering our position a few months ago," Lampard said.
"But football is like that. You can never take anything for granted. You could never accuse us of giving up no matter how difficult our position was. More importantly, we have to believe we can go to Old Trafford and win the game.
"Of course it’ll be extremely difficult but we’re more than capable of doing it."
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