In order to unlock the Battle Royale Tournament you will need to have earned at least a
gold medal on all of the previous tournaments.
This tournament consists of 21 events played against 8 players, so can take a while to complete.
Most of the events are attack orientated (Chaos, Hunter, Flag, Takedown, Street Trace)
I won the gold medal on this quite easily as by this point in the game I knew what I was doing, had worked out some good strategies and with 8 players quite often the points are shared out, you can build a good lead providing you are winning or getting podiums on most events.
I also used this tournament to unlock
This will come easily as there are plenty of events, I focussed on money in the early events and spent it on weapons, this helped me takedown the other riders easier and earned me the points needed to win in most events, by the last event I had 55K in the bank and a full upgraded board.
I also used this event to get
You get 15 points for Gold & 20 for Platinum on the first 3 unlocked tournaments, then 30 points for gold on the last 2, add in the points needed for getting a Bronze time trial and you will have enough to pass the 100 mark.