If you wanna buy real tickets last minute, try to go to the ticket office outside arena on the day of the show. They usually open the same hour they let people in (it was 7 PM here in Barcelona). It’s good to be an hour or two earlier to save a spot in the queue. They have extra tickets (not a lot), I bought that way a golden circle ticket an hour before the show. And yes, while waiting, a lot of people were approaching trying to verify their tickets and all of them were fake if bought through Viagogo :/

I appreciate this and will definitely give it a shot.

btw, if tickets were transferred to you through Ticketmaster, they are valid. It’s the only 100% safe option