Ryuji Suguro is Rin’s rival and he has been shown to be able to keep up with Rin academically. That being said, a fight is about combat skills and Rin is clearly superior in that category. Ryuji hasn’t been able to get anywhere near Rin when it comes to fighting and you can safely say that the Rin from volume 1 could beat the current Ryuji. That’s pretty sad for the big rival of the series, but maybe he will improve someday. Rin Okumura wins.