The defender made his debut as a second-half substitute against Belgium and then started the meeting with Denmark three days later.
His red card for dissent to the referee after the final whistle proved a sour note to end what had been a very promising camp for the 20-year-old and Lampard admitted he was hardly surprised at the youngster's swift adaptation to senior international football.
"I thought his performance was very good," said Lampard. "I sort of expect that because I expect a lot from Reece, although you should probably never expect that on a full debut.
"He showed his comfort in the game against Belgium before that when he came on, where it looked like he'd been playing for a long time, and his performance against Denmark was also really good.
"His progress has been phenomenal. It was when he played at Wigan in the Championship - I followed him closely and tried to take him to Derby in the January window but it didn't happen. I've always been a big fan of his in terms of his.
"There are things he'll want to improve in his game and the great thing about Reece and a lot of the other younger players at the club is that they're very open to that and they want to improve all the time. He has great natural talent, great physical attributes, can be worked on and he's going to be a fantastic player for this club for a long time."
Lampard admits he did have a quiet word with James on his return to Cobham this week about the circumstances of his dismissal, England's second of the night.
"I did have a word with him about the end and the fact he got involved with the referee," continued Lampard. "We're all human. I've been there and done it as a player and maybe as a manager as well.
"None of us are saints but it will definitely be one for him to learn from. When you have a performance of that level playing for your country you'll get a lot of plaudits and there was no need for him to get involved with the referee after. It was a pretty simple conversation and something he'll definitely take on board."