The summer signing was impressive for the Blues against Aston Villa in their 2-1 win in the Premier League on Wednesday night.
Pulisic had a fight to earn his spot in Lampard's starting lineups this season, but he has made key goalscoring contributions in the past few weeks.
Lampard told reporters on Pulisic after the Villa game: "He is playing really well.
"He can score more, we have a player in Christian who is someone who is really exciting us but when you see this type of player, you see another level which is goals and assists and he has the ability to go on to that extra level which is the top level of world football.
"At the moment he is doing really well and hopefully that will be the next part of the progression."