RB Salzburg manager Jesse Marsch, also from the US, recently claimed that Lampard had reservations about Pulisic because he was from America.
However, Lampard has categorically refuted Marsch's interpretation of a conversation which took place when the two clubs faced during preseason.
He told reporters: "I did read the comments and I was surprised that Jesse had managed to read my mind as well as he thought he did. He's recounted the conversation wrong so I have to put it correct. It was a game against Salzburg in pre-season where Christian scored two goals and I spoke to Jesse after about what a talented player he was and how exciting it was to see how he could develop for us with the talent he has. That was the conversation and Jesse managed to put it across slightly differently.
"I played in America for 18 months and I would never underestimate the desire that American players have to learn and improve and take on information and understand the technical side of the game. When you have that, which Christian has, along with incredible talent, it was never in doubt for me.
"It's clearly the toughest league in the world to come and play in at a young age from a different league. Some of the greatest players in Premier League history have felt that. What Christian did was find his feet very quickly and have a breakthrough season where he produced more goals and assists than he has done before so I thought his performance last season was massively impressive and he will keep getting better and I never doubted it in the first place. As a manager, I never doubted him and it's important for me to put that straight."