Pokemon XY&Z - episode 25 - 04 May, 2016

Champion Diantha visits Ash and his friends in order to discuss the prophecy foretold by Olympia. Learning about Ash and Greninja's unique power, Diantha and Mega Gardevoir engage in battle against Ash-Greninja. As the battle progresses, Ash and Greninja's power reaches a new level, pushing Diantha to the brink of defeat, but Ash passes out once again before the battle can be decided. (Source: Wikipedia)