The 20-year-old is highly rated at Selhurst Park, to the point that Eagles Under-23s coach Richard Shaw compared him to Manchester United and England legend Bryan Robson (Football London).
Dreher, working his way back from injury, scored his first goal since his return, tapping home from close range in the second half after Levi Lumeka had made his way down the left and pulled the ball back for his teammate.
Leeds U23s had been leading after the interval following Ryan Edmondson's opening goal in the first half, rifling past Lucas Perri after Jack Clarke’s cross had been headed down to the striker.
The Whites then regained the lead through Mateusz Bogusz, who got the better of Ryan Inniss before slotting past Perri, but Palace substitute Kian Flanagan made sure of honours even with his fierce drive into the bottom corner via the post.
With Leeds sitting top of the Professional Development League North, Dreher admitted that he and his Eagles teammates were always set for a tough afternoon.
"It was good, they're a good side," he told the official Palace website. "They're top of the league so we knew coming into it they're a really good side. We knew what they were about: they like to press you, like to get in your face.
"It was a good game, there were lots of chances and the boys did well. On the balance of it, we probably should have won it but we created quite a few chances, clear-cut chances which on another day we could have scored. It was a good game to play in."