The Italian believes that there is a lot of quality in his side and is confident ahead of the club's Champions League quarter-final first-leg tie against Benfica
The midfielder's assesment comes as Chelsea remain five points behind Tottenham in fourth place in the Premier League and are in danger of failing to secure a spot in the Champions League next season.
"The numbers say that, so there is no point in denying it's been a difficult season," said Di Matteo.
"But we have quality in this team and many good players. I still think this Chelsea team is a very good team."
The Blues face Benfica in the first leg of their Champions League quarter-final tie on Tuesday evening and Di Matteo insists that his side can secure an advantage to take back to Stamford Bridge next month.
"It's a very fine line between success and failure, this team has the ability to play a good game tomorrow night," the Italian continued.
"Benfica play with great intensity and good pressure, have some excellent players, wouldn't be in the quarter-finals if not."Despite Lampard's criticism, Di Matteo maintains that his side are buoyant ahead of the pressurised run-in.
"I am positive about the team, but my players are positive too," he added.
"We have great belief in our abilities. That's what we're going to try and express tomorrow."