#1 Matt Riddle
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Before he made it to NXT TV, Kushida actually teamed with Riddle at several NXT house shows, but now that he's made it to the big stage, this is a match that needs to happen as soon as possible.
There are other new talents still on the brand like Dijakovic, Keith Lee, and others waiting in line like Trevor Lee, Shane Strickland, and so on, but given the hype for his debut, Kushida needs to become a big priority.
Both men are physical and able to wrestle different styles, so if given enough time, they could have a physical, fast-paced bout that would be worthy of a TakeOver main event. This one may not happen for a while, as both men will likely be chasing gold in the near future, but when it does happen, both men will be established as future main event stars of WWE.