Cresselia92
SM Ash = New Ash
Also, how does Ash forget about Serena? I mean assuming he is 10 years old and you gotta imagine that he bandaged Serena when he was 6. I know time works differently in the Pokémon world but that probably still wasn't that long ago. I would understand if he was 20 or something but he's 10 so it really wasn't that long ago.
I find that perfectly natural, to be honest. It's virtually impossible to remember the hundreds and hundreds of people you see during your life. When I was 6-7, I remember swimming with a girl who knew English and Spanish. However, I don't remember anything else. No name and no face. If I saw her again I would probably not recognize her. Same goes for a lot of people that I've seen during my life.
So it makes sense that Ash doesn't remember her. She probably was a girl like others to him and probably didn't leave him any impact. Serena, to the contrary, got said impact.
Different people remember different things because they have different minds. He may slowly remember her while they travel together.
Anyway, I'm a bit disappointed that Pikachu got two wins. I would have preferred if he lost to Vivillon and let Fletchling finish the job. Oh well, the battle and interactions seem interesting nonetheless.