When Yuya was battling Yuuri, during battle, Yuya never used his pendulum effect, including the time when you know... HE COULD'VE PREVENTED THE TOKEN TRAP CARD AND DESTROYED STARVE VENOM ON HIS FIRST TURN AND YURI WOULDNT HAVE HAD TIME TO MAKE HIM WANT TO BECOME ONE WITH HIM!
Edit: Since the trap wouldn't activate, Starve Venom would be destroyed, Yuri gets attacked with coin dragon and cannot recover since he has only had a high-level monster in his hand. So Yuri would be down to 1400 life points from the first turn and because he would've had 3 cards at the start of his next turn, which one is confirmed to be level 6, Yuri sets a card which leaves 1 card in his hand that isn't confirmed until and his next turn, he sets both cards in his hand face down. Literally, 2 turns and Yuya would've won.
So if we eliminate the possibilities, Yuri wouldn't be able to summon a monster, his hand being a level 6 monster, a trap card that would take a dragon if Yuri had one of the Dragons on the field, which wouldn't be the case, and either Predator Plant Reborn or Ridicule World which would have either done this; Summon a Predator Plant that could summon the best case scenario, Predaplant Ophrys Scorpio which summons another level 3 or lower predator plant, but since Yuya would have 3 monsters, that would've only delayed a small bit. With Ridicule World, he would've prevented a turn of attacking but wouldn't get a card to defeat Yuya. No need to discard Smile World.
No losing Smile World, no "You need to win Yuya" none of that. NO ZARC AND IT'S ALL YUYA'S FAULT FOR NOT USING THE PENDULUM EFFECTS!
OK, rant over.