The midfielder refused to pull his punches, admitting the Blues let their standards drop after their historic comeback against Napoli. Since that result, they have reached the FA Cup semi-finals but have taken just one point from two Barclays Premier League games to slip five points behind fourth-placed Tottenham, who drew 0-0 at Stamford Bridge on Saturday.
Lampard told Chelsea TV: "The fixtures and where we are in the table doesn't lie - we're not as good as we used to be. We used to have a fortress here and, for whatever reason, we're just not doing it. It's something we must all put right."
He added: "You know a derby against a very good Tottenham side is going to be tough. But I don't think we were at it enough. We had to play more with the urgency we showed against Napoli. Against Tottenham, we didn't really do enough to lift the fans. We had the high of Napoli, then we got beaten by Manchester City and now we need to up it again."
Chelsea, who face Benfica on Tuesday in the first leg of their last-eight tie in the Champions League, have finished in the top four for nine successive seasons.
Lampard said: "Chelsea should be in the top four. No disrespect to the other top-five clubs but, with the ability we have, we should be in there. It is far from over. There is no point being downbeat about it at the minute.
"It's five points and the gap has been bigger than that. It's up to us now to get ourselves right for Benfica and the league games coming up."
Admitting Chelsea were outsiders in the race for fourth place, Lampard added: "That's due to dropping points throughout the season, not drawing with Tottenham at home.
"It's losing games we should have won home and away. We have to take all the league games now as knockout matches.
"It's very cliched but we're fighting from behind, and if we lose a game and lose points then the gap is bigger and the amount of games left is shorter. So we know, especially after that draw, the gap is still five points and there is no more room for slip-ups."
Source: PA
Source: PA