The following season, Irwin suffered a hamstring injury in the Toronto FC's home opener, a 0–0 draw against Sporting Kansas City; as a result, Bono was once again promoted to the starting line-up in Irwin's absence, and eventually established himself as the team's outright first-choice shot-stopper by September 2017, due to his performances, even after Irwin's return from injury. In a rematch of the previous season's MLS Cup Final, on December 9, Toronto defeated Seattle 2–0 at home to capture the 2017 MLS Cup, and complete an unprecedented treble of the MLS Cup, the Supporters' Shield, and the Canadian Championship.