When an opponent moves a unit to an open battlefield starting a showdown, and you play Zenith Blade at Action speed to move your unit to that battlefield, what happens? Does the opponent score for conquering the open field, and what is the sequence of events?

Ruling: When Zenith Blade moves your unit to a battlefield during an open showdown, the unit contests the battlefield and a pending combat is created. The open showdown does not result in a conquer (control cannot be established while contested), and once the open showdown ends, combat begins with the original player as the attacker and the Zenith Blade player as the defender.

Sequence:

• Opponent moves unit to open battlefield, starting showdown
• Zenith Blade resolves, moving your unit to that battlefield
• Your unit contests the battlefield and creates a pending combat
• Open showdown resolves without conquer (control cannot be established)
• Combat begins with opponent as attacker, you as defender

Nuances:

• If the unit that was moved in via Zenith Blade is removed from the battlefield before the pending combat starts (e.g., via another spell like Rebuke), the pending combat no longer occurs per rule 622.2, and the opponent would then conquer the battlefield
• The player who originally applied contested status to the battlefield becomes the attacker in the resulting combat
• If both units remain after combat due to stun and the attacker's unit is recalled, the defender gains control and scores on defense