Wing-back James rifled home the Blues’ final goal in an emphatic 3-0 Stamford Bridge success over the Serie A champions, having set up Pierre-Emerick Aubameyang’s strike following Wesley Fofana’s first-half opener.
A fine evening for the hosts was marred only by £72million summer signing Fofana limping off due to a first-half knee injury which has left head coach Potter “concerned”.
Yet the former Brighton boss was full of praise for England international James, claiming he could become a club “legend”, after Chelsea got their European challenge back on track following just a single point from their opening two Group E fixtures.
“I think Reece is just a fantastic player and he’s a young player, so he’s developing all the time,” said Potter. “He’ll get better and better as we go. I’ve really enjoyed working with him, he’s got a lot to offer.
“He can play in any game in the world, he’s just tremendous. My job is to try and help him reach his potential because his potential is beyond the sky.
“For us, we love him. He’s so important for us. He could be a Chelsea legend, that’s the level that he has, the potential that he has.
“But for that to happen he has to be part of a successful team and that’s what we’re working towards.”
Centre-back Fofana claimed his first Chelsea goal by finishing following a goalmouth scramble with 24 minutes on the clock in west London.
But the French defender soon departed and later left the ground on crutches and wearing a knee brace, leaving Potter with an anxious wait to discover the extent of the issue.
Aubameyang’s second goal in two games following James’ fine right-wing cross put the Blues in complete control early in the second period before the latter put the game beyond the Italian visitors with a thunderbolt into the roof of the net.
Speaking about Fofana’s issue, Potter said: “We don’t know yet. That’s the one disappointing thing about the evening. We need to scan tomorrow and fingers crossed.
“I wouldn’t want to speculate on it now but we’re concerned and we need to just wait for tomorrow, get it scanned and hope for the best.
“These things happen, he’s a young guy, a strong guy, we’ll support him. But like I said at the moment not too much to report but we’re hoping for the best.”
Rade Krunic squandered a golden chance to draw the away side level just before the interval but they created little and were comfortably second best.
Milan manager Stefano Pioli said his players are “hurting” and challenged them to respond during Saturday’s home clash with Juventus before Chelsea visit the San Siro next week.
“We could have done much better,” he said. “It’s clear that our opponents played at a very high level but in our decision-making we weren’t accurate enough.
“We didn’t start the game particularly badly but after a couple of minutes we tried to do things that weren’t part of our game and our opponents were able to exploit the space in behind us, they were so quick.
“We need to try and reverse this result at the San Siro in the next game.
“This being a heavy defeat has to make us react quickly. We’re hurting but that’s going to give us even more determination and more focus when we prepare the next game, which is going to be very difficult.”