Andy Murray made a winning start to 2019 but admitted he does not know how much longer he will be able to play top-level tennis after hip surgery.
Britain's former world number one beat Australian wildcard James Duckworth 6-3 6-4 at the Brisbane International in his first match since September.
Scot Murray, 31, struggled to contain his emotions as he told how last year had been "really hard".
Fellow Briton Johanna Konta beat 2017 US Open winner Sloane Stevens 6-4 6-3.
Murray is a three-time Grand Slam winner but currently ranked 240 in the world after only playing six tournaments in 2018.