18 year old Hyeon Chung has been rocketing up the rankings since 2015 began, and is fast approaching the top 50 in the world. He's won several Challengers already this year, and reached the finals of another this week. He's quickly becoming one of the most promising prospects in men's tennis, though it remains to be seen how his success will translate on the ATP Tour.
Chung plays a somewhat unorthodox game, and he has a tendency to "guide" some of his forehands, somewhat reminiscent of Bernard Tomic. He's capable of hitting out on it, but seems to leave more than he'd like a bit short. Part of the problem is he tends to keep his left hand in front of his body for too long, which stops him from swinging across his body on his follow through. If he can fix this it would make life on the ATP Tour much easier, as it's hard to dominate without a reliably big forehand.
The most successful pros generally spend relatively little time on the Challenger circuit, as they're good enough to get enough points to reach the ATP level in little time. Chung appears to be well on his way to becoming an ATP Tour regular, which is a promising sign at only 18. However, just because players dominate at the Challenger level doesn't mean their success will translate to the ATP Tour.
A few years ago, Pablo Carreno-Busta won countless Challengers and futures titles, and surged onto the ATP Tour. However, once he had to start playing ATP tournaments as opposed to Challengers, he discovered it became much more difficult to rack up ranking points. He hasn't been a disaster on the ATP tour, but he's hardly seen big time success. This isn't to say the same will happen to Chung, just that there's no guarantee Challenger dominance will turn into ATP Tour success.
If Chung continues to tweak with and improve his forehand and serve he could be a serious factor on tour within the next few years. He's clearly got a lot to work with, and seems to get better each week. Few teenagers have reached the levels he has in recent years, and it's time for more people to take notice of his success. If he can keep it up at the next level, getting people to take notice won't be a problem.