Andy Murray has revealed he is unsure how much longer he will be able to play competitively. 

The 31-year-old returned at the Brisbane International on Tuesday, after hip surgery ruled him out for much of last season. But the Scotsman admits there is no long-term goal in mind when it comes to a full comeback. 

Murray appeared to fight back tears after beating Australian James Duckworth in straight sets at the Brisbane International, which is his first match since last September's Shenzhen Open. 

"It's not easy to sort of sum up in one sentence or one answer, it's been, it's been a really hard 18 months. Lots of ups and downs, it was tricky just to get back on the court competing again, so I'm happy I'm back out here again, " said Murray. 

The former World Number One's season was ended early last year, after he suffered pain in his hip following surgery earlier in 2018 that ruled him out of three of the four Grand Slam events. 

The Brit's ranking has now dropped to 240. Earlier the 3-time Grand Slam winner said he was still feeling discomfort, but was in a better place than that of 12 months ago. 

"I want to try and enjoy it as much as I can. Just try and enjoy playing tennis as long as I can. I don't know how much longer it's going to last, but we'll see," he added.