Andy Murray made a first-round exit from the Brisbane International after Grigor Dimitrov came from behind to win in three sets.
Bulgarian second seed Dimitrov triumphed 4-6 7-5 6-2 to progress at the season-opening tournament.
The defeat is a setback for Murray's preparations for the Australian Open, which starts on 14 January.
It comes after the Briton said the 2024 season could be his last on tour if he is "not enjoying it".
The 36-year-old struggled with a shoulder injury in the latter months of 2023, while illness and a bruised knee made for what he described as a "tricky" pre-season in an interview with BBC Sport before the Brisbane event.