CSGO finals had about 3m https://www.dexerto.com/news/e-league-csgo-major-breaks-view...
The 2017 Superbowl as one example, had 114M. http://money.cnn.com/2017/02/06/media/super-bowl-ratings-pat...
The UEFA Champions League final in 2016 attracted 350 million global viewers.[1] I am supposing the 2017 event wasn't too much less than this.
The 2017 Indian Premier League (IPL) final had 324 million viewers according to one source.
[1] http://www.pennlive.com/sports/index.ssf/2017/02/super_bowl_...
[2] http://www.espncricinfo.com/story/_/id/19660717/billion-peop...