World number nine Felix Auger-Aliassime has withdrawn from this week's Dubai Tennis Championships with a back problem, the organisers of the ATP 500 tournament said on Monday.
The 21-year-old Canadian is at a career-high ranking and defeated French Open runner-up Stefanos Tsitsipas in the final in Rotterdam this month to secure his maiden ATP Tour triumph.
He also reached the final of the ATP 250 event in Marseille last week, going down to Russian Andrey Rublev in the championship match on Sunday.
Auger-Aliassime was seeded third in Dubai and was replaced in the draw by lucky loser Alexei Popyrin of Australia.
Serbian world number one Novak Djokovic is the top seed and will open his campaign later on Monday against Italian wildcard Lorenzo Musetti in his first match of the 2022 season.