Roark has some pretty sturdy Pokemon at his disposal. The problem for him is that Ryoma can serve at incredibly high speeds so sheer numbers aren’t enough to scare him. Ryoma is perfectly prepared to deal with as many shots as he needs too deal with in order to win. Roark’s best plan is to try to separate Ryoma from his racket since the kid will be powerless without it, but that’s much easier said than done. I don’t see such a plan working to be honest. Ryoma wins.
Update 8 7 2020 Roark is just too fast for Ryoma. Roark wins.