Mackenzie qualified for his 3rd PDC World Championship in 2015 where MacKenzie reached the final of the 2015 World Championship PDPA qualifier and lost 5–2 to Jason Hogg. However, it was enough to earn him a spot in the preliminary round of the event where he raced into a 3–0 lead over Daryl Gurney and missed one dart to win 4–0. Gurney levelled the match at 3–3, before MacKenzie missed a dart at double 11 to complete a 142 finish and was defeated 4–3. MacKenzie and Lam caused a couple of shocks at the World Cup. First they defeated Wales' Mark Webster and Jamie Lewis 5–3. Lam then beat Ireland's William O'Connor 4–1, but MacKenzie missed six match darts against Connie Finnan from 3–0 up to lose 4–3 meaning a doubles match was needed to settle the tie. It went to the final leg in which MacKenzie finished 86 to send Hong Kong into the quarter-finals. However, number two seeds Scotland proved to be too much as Gary Anderson and Peter Wright won both their singles matches 4–2 to eliminate Hong Kong. MacKenzie claimed the 2015 Hong Kong Open by beating Alex Hon. Mackenzie and Lam represented Hong Kong for a third successive time at the PDC World Cup in 2016 where again they played Ireland, a team consisting of William O'Connor and Mick McGowan, and they eventually lost 5–4 in the first round.