Top seed and defending champion Andy Murray started his year with a 6-1 5-7 6-3 victory over Australian qualifier John Millman at the Brisbane International.
The British number one, who lost to Janko Tipsarevic at his season-opening exhibition event in Abu Dhabi last week, raced through the opening set before encountering more resistance in the second.
Millman, the world number 199, broke in the seventh game but faltered when serving at 5-4 to level the match.
He was given a second chance as Murray handed the break straight back and this time Millman was able to serve it out. But the Scot quickly restored order in the decider and closed out victory after two hours and five minutes.
Despite looking in pain at times in the third set, a relieved Murray said: "I think it was a pretty high-quality match. The first set wasn't that comfortable. He gained confidence and started going for his shots more.
"He was returning my first serve extremely well and playing right up on the baseline and just going for big shots. It was tough for me to dictate too many of the points.
"I made some adjustments with the way I was serving in the third set that turned it around, but he played really, really well for the most part."
The US Open champion will play Denis Istomin in the third round after the Uzbek beat wildcard Lleyton Hewitt 7-5 7-5.
Second seed Milos Raonic crashed out in his second-round match, the Canadaian going down 6-3 6-4 to Bulgaria's Grigor Dimitrov.
Also on Thursday, seventh-seeded Austrian Jurgen Melzer overcame Belgium's David Goffin 6-4 7-6 (7/4).