The young goalkeeper, just 18, made his debut off the bench in the third match of the Tour against Chicago Fire on Saturday.
The Academy graduate played 17 times for the Under-18s, both FA Youth Cup ties and started twice for the Under-21s before signing professional terms in July.
“The Tour has been a great experience,” said Luke. “It’s a big step up in load and quality but I think I adapted quite well and I’ve come out of it a better player.
“I was a bit nervous before I went on against Chicago but I didn’t do too badly. It was a good start for me.
“It’s great to get a debut but I have to kick on from here. I don’t just want to make one appearance, I want to continue to improve and to build from here.”
Luke has trained with the first team and new goalkeeping coach Toni Jimenez throughout pre-season.
“I’ve given everything to show what I’ve got and to try to leave a leasting impression,” he added. “All I can do is keep working hard and see where that takes me.”