After nine successive seasons of top four finishes in the Premier League, Chelsea find themselves in fifth place with just eight games remaining.
The weekend's goalless draw with Tottenham Hotspur leaves the Blues five points adrift of their North London rivals in fourth place.
Frank Lampard told Sky Sports: "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."
The Blues have struggled against the current top four this season, with victory over Manchester City at Stamford Bridge the only win they have achieved so far.
Chelsea had the chance to do the double over City last Wednesday as they led 1-0 until the last 15 minutes at the Etihad Stadium, but Sergio Aguero and Samir Nasri, ensured that the home side took all three points.
Manchester United have had the better of the league encounters this season winning 3-1 at Old Trafford and coming from behind to draw 3-3 in west London.
After losing 5-3 at home to Arsenal, Chelsea drew both games with Spurs which gives them a total of just six points out of a possible 21 against the top four - with a visit to the Emirates Stadium on April 21 still to come.
Roberto Di Matteo's men are now outsiders for a fourth placed finish, but Lampard is still confident of realising the club's goal.
"It's losing games we should have won home and away," he continued. "The fixtures and where we are in the table doesn't lie - we're not as good as we use to be.
"We used to have a fortress here and, for whatever reason, we're just not doing it. It's something we must put right.
"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."