I may be misremembering considering how many chapters it takes to get through just a couple rounds and how many hypothetical situations get played through, but I thought Kazuya had a queen anyway.
Obviously he cheated, but my point is that Kaiji's breakthrough hinges on Kaiji "realizing" that Kazuya couldn't possibly have saved the higher of his two UP cards from the earlier round. But, in fact, I am pretty sure Kazuya did save his higher UP.
In other words, I'm pretty sure Kazuya would have won that round even without cheating.