For a time, he was primarily a Magic: The Gathering Online player, but made the transition to in-person competitive play.

[17] He has since 2012 been a part of the team now known as 'The Pantheon', alongside players such as Jon Finkel, Kai Budde and Gabriel Nassif.

[20] Thanks to three Grand Prix top eight finishes, in Charleston, San Antonio and Quebec City, as well as stellar performance on the Pro Tour, he succeeded in requalifying for the World Championship when he finished 9th at Pro Tour Dragon's Maze in San Diego.

At Pro Tour Journey into Nyx in Atlanta, Duke finished fifth, losing in the quarterfinals to Yuuki Ichikawa.

[9] At this point, he was in position to win the 2013–14 Player of the Year title, but ultimately this was won by Jérémy Dezani.

[25] At the 2014 World Championships, however, Duke posted a modest 14th-place finish, and his Pro Tour results throughout the season were average.

He managed to reach two Grand Prix top eights, in Singapore and Montreal, towards the end of the season to retain Platinum status, but he did not qualify for the 2015 World Championships.