"Synchro Straits", known as "After Sealing Synchro Summoning..." in the Japanese version is the seventy-third episode of Yu-Gi-Oh! 5D's. It first aired in Japan on August 26, 2009.
Yusei recalls his fight with Ghost before and challenges Jack to a Duel. Yusei tries to find ways to fight without using Synchro Summoning, but Jack ends up cancelling the Duel, as he feels not using Synchros is weak. There, a masked man watches the worried Yusei. Later on that day, the gang goes to the WRGP party.
Yusei is still greatly bothered by not only Ghost and his "Meklord Emperor Wisel", but also by Sherry's words to him during their Duel. He is unable to get rid of his fear of Ghost, so he asks Jack to Duel him. He chooses not to use Synchro Monsters during the Duel in order to help him find a counter to the Synchro-absorbing effect of Ghost's "Meklord Emperor". The Duel ends by Jack's request due to Yusei's state of mind. Jack tells Yusei he should still use Synchro Monsters, with Crow noting that the effect of "Wisel" is still a problem. Unknown to all of them, a mysterious individual was watching the whole time.
Later at the party, the WRGP is being announced to all the people of New Domino City and the gang meet Team Unicorn, specifically Andre and have a brief talk with the group. During all of this, Yusei is still greatly bothered and Akiza knows that Sherry's words to him are still greatly bothering him and something needs to be done about it. Yusei also notices someone passing by him but doesn't get a good look at him.
Turn ?: Enemy
Enemy has just Tribute Summoned "Tiger Dragon" in Attack Position. The effect of "Tiger Dragon" activates, destroying Yusei's two set cards. "Tiger Dragon" attacks and destroys "Speed Warrior" (Yusei 1800 → 300).
Turn ?: Yusei
Yusei's hand contains "Turbo Booster" and "Limiter Overload". Yusei draws "Debris Dragon". During the Standby Phase, the effect of "Speed World 2" activates (Yusei's SPC: 5 → 6; Enemy's SPC: 5 → 6). Yusei Normal Summons "Debris Dragon" (4/1000/2000) in Attack Position. Yusei then activates the effect of "Debris Dragon" to Special Summon "Sonic Chick" (1/300/300) from his Graveyard in Attack Position with its effects negated. Yusei then tunes his "Shield Warrior" and "Sonic Chick" with "Debris Dragon" in order to Synchro Summon "Stardust Dragon" (8/2500/2000) in Attack Position.
At this point, the enemy is changed into Ghost while the Enemy's "Tiger Dragon" is changed into "Machine Emperor Wisel ∞" (1/0/0) in Attack Position, "Wisel Top" (1/500/0) in Attack Position, "Wisel Attack" (1/1200/0) in Attack Position, "Wisel Guard" (1/0/1200) in Defense Position, and "Wisel Carrier" (1/800/600) in Attack Position. Due to the effect of "Wisel ∞", its ATK becomes equal to the combined ATK of all the other Wisel monsters that Ghost controls ("Machine Emperor Wisel ∞": 0 → 2500/0).
Turn ?: Ghost
Ghost draws. During the Standby Phase, the effect of "Speed World 2" activates (Yusei's SPC: 6 → 7; Enemy's SPC: 6 → 7). He then activates the effect of "Machine Emperor Wisel ∞", equipping itself with "Stardust Dragon" and increasing its ATK by the ATK of "Stardust Dragon" ("Machine Emperor Wisel ∞": 2500 → 5000/0).
The Duel, at this point, ends with no result as it turns out to be a nightmare that Yusei had and he had woken up from it.
Yusei Fudo vs. Jack Atlas
Turn 1: Yusei Yusei draws "Shield Wing" and subsequently Normal Summons it (2/0/900) in Defense Position. He then sets a card.
Turn 2: Jack Jack draws. During the Standby Phase, the effect of "Speed World 2" activates (Yusei's SPC: 0 → 1; Jack's SPC: 0 → 1). Jack then Normal Summons "Twin-Sword Marauder" (4/1600/1000) in Attack Position. "Twin-Sword Marauder" then attacks "Shield Wing", but due to the latter's effect, it is not destroyed, however "Twin-Sword Marauder" still inflicts piercing damage to Yusei (Yusei 4000 → 3300). "Twin-Sword Marauder" then attacks "Shield Wing" once again due to its first effect. Due to the effect of "Shield Wing", it is not destroyed, however "Twin-Sword Marauder" then inflicts piercing damage to Yusei (Yusei 3300 → 2600).
Jack then Special Summons "Sword Master" (3/1200/0) in Attack Position from his hand via its own effect as "Twin-Sword Marauder" attacked "Shield Wing", but was unable to destroy it by battle. "Sword Master" then attacks and destroys "Shield Wing". "Sword Master" then inflicts piercing damage to Yusei (Yusei 2600 → 2300).
Yusei then activates his face-down "Synchro Deception" to send "Junk Warrior" from his Extra Deck to the Graveyard and increase the ATK of "Backup Warrior" by half the ATK of "Junk Warrior" ("Backup Warrior": 2100 → 3250/0). "Backup Warrior" then attacks and destroys Jack's "Sword Master" (Jack 4000 → 1950). On Yusei's End Phase, the effect of "Synchro Deception" expires ("Backup Warrior": 3250 → 2100/0).