He got to the third round of the World Championship for the second year in a row with comfortable victories over Jeffrey de Graaf and Brendan Dolan, but found himself 3–1 down to Dave Chisnall. Klaasen took the next set and led by two legs to none in the sixth, before Chisnall won three legs on the spin to triumph 4–2. His return to the Premier League was blighted by tendinitis in his wrist for which Klaasen received anti-inflammatory injections before matches. Klaasen explained how he could play for five or six legs before experiencing pain in his throwing hand. His only win out of his nine league games came against Chisnall and Klaasen finished ninth in the table to be eliminated. He lost 6–2 in the final of the German Darts Masters to Van Gerwen.