The young attacker started against the Blues and guided Palace to a 2-0 lead inside 12 minutes, before claiming the match ball in the second-half with a well-taken finish.
He played 70 minutes to add to his time against Millwall and Accrington Stanley, with Roberts confirming the coaching staff are happy with his start to life in south London.
“Luke is settling in really well,” the assistant manager said. “He got a few goals today and is a real threat. His movement is really good and from his first day here we’ve been really pleased with how he adapted, but at the same time [we're happy with how he] is progressing and taking information on board while working really hard.