Link v.s. Riku

v.s.

Link is his Wind Waker and TP version

Riku is his KH2 and Chain of Memories version

Takes place in Memory's Skyscraper.

Depends a lot on whether or not Riku is allowed to transform into Xehanort's Heartless and use the power of Darkness. If so Link gets pwned to oblivion, no question. Even Dark Riku from Chain of Memories should take this easily. One Dark Aura would be more than enough.

If it's just the basic versions, it would be close, but Riku should still take it. He's just as fast, can create sheilds and spam Dark Firagas.

Both versions of what you said, use Xehanort's heartless.

Link can go Dark.

Riku blocked so many of Xemnas's projectiles at speeds that would make Link look like a slug.

Riku speedblitz' Link

I say Riku can do it, but with alot of effort.