The 18-year-old got the Eagles off to a flier with a goal after just two minutes and then turned in a man-of-the-match display to see off woeful Watford as Alan Lee and Darren Ambrose completed a 3-0 win at Selhurst Park.
Warnock said: "There was interest in the summer but they wouldn't take the gamble.
"People have doubts about his temperament but I think he'll blossom the higher he goes."
Watford's Danny Graham had a penalty saved by Julian Speroni, and manager Malky Mackay said: "Palace may not be able to spend big on players, like us, but if you looked at their team they had played a lot more games than my lads at this level."
