Montreal's Felix Auger-Aliassime had his comeback attempt fall just short in a 7-5, 4-6, 7-6 (5) loss to Andrey Rublev on Friday in the semifinals of the Qatar Open.

Down 6-3 in the third-set tiebreaker, Auger-Aliassime scored the next two points on serve. But when the serve rotated to Rublev, the fifth-seeded Russian converted on his third match point.

Auger-Aliassime lost despite firing 21 aces in the match. The world No. 23 failed to convert what turned out to be a crucial break-point chance in the first game of the third set as the players held serve the rest of the way.

Rublev took the first set when he broke Auger-Aliassime in the clinching game, but the Canadian responded with a strong second set in which he fired seven aces and won 81 per cent of service points.

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Rublev improved to 6-1 against Auger-Aliassime and will next face the winner of a match between eighth-seeded Briton Jack Draper and Czechia's Jiri Lehecka, who advanced to the final four with a shocking quarterfinal upset of top seed Carlos Alcaraz.

Auger-Aliassime had advanced to the semifinal of the ATP 500 tournament after fourth seed Daniil Medvedev retired from their quarterfinal with food poisoning after dropping the first set 6-3.

The 24-year-old Canadian has a 14-4 record this season after winning titles last month in Adelaide, Australia and Montpellier, France.