The video game championship, known simply as TI4 by the initiated, boasts a rapt audience of millions and a prize pool approaching $11 million US.
That's the richest purse yet for a video game tournament, but we're not talking some old school arcade rivalry.
TI4 is a competitive event so huge it's beginning to blur the lines between online gaming and traditional sport.
Defense of the Ancients 2 –or Dota 2 as it's more commonly called – is a multiple player battle arena game. While the game play is virtual, the money involved is very real.
More Internet traffic than Facebook
The vast majority of the fans are following the action online –including 300 people in Toronto who actually rented a movie theatre so they could watch together – via live streaming site Twitch.tv.
During its peak hours the online broadcast site creates more Internet traffic than Facebook, and industry reports say Google is in talks to acquire Twitch for more than a billion dollars.
For the past four days, devoted Dota 2 fans have been absolutely buzzing about TI4 on sites like Twitch.
When the tournament's victors are declared on Monday night, not only will they have seized a record-breaking multimillion-dollar pot, but the winners and their fans will have helped prove that competitive gaming is a powerful new a force in entertainment.
Be sure to tune into The National tonight for the full story with Eli Glasner.