Veteran Lleyton Hewitt survived 20 aces from big-serving Canadian Milos Raonic to post a 6-3 1-6 7-6 (7/4) victory at the Kooyong Classic in Melbourne.
The Australian, bidding to recapture the title he lifted in 2011, reeled off six consecutive points in the final set tie-break after world No 15 Raonic seized a 3-0 lead.
The 31-year-old former world No 1, who will compete in a 17th straight Australian Open next week, sealed victory on his second opportunity after Raonic had saved a match point with an ace.
And the former Wimbledon and US Open champion, who has slipped to 82nd in the world rankings, is happy to be competing pain-free after several years of foot and toe problems.
"I feel mentally fresh and just excited to be playing without pain," said Hewitt. "The last few years have been frustrating, trying to play with injuries.
"I'm amazed at how many Opens I've played, but I don't focus on the record -- it only makes me think how old I am. But when I retire I'll be pretty proud of it."
Argentine Juan Martin del Potro beat Frenchman Paul-Henri Mathieu, a late substitute for injured Argentine Juan Monaco, 6-4 3-6 7-6 (7/3).
"It was a tight match to start the year, I tried to play the best I could. The weather was sometimes horrible to play in with the wind and the sun," said Del Potro. "But this is a very good chance to prepare for the Australian Open."
Del Potro will next play 2006 Australian Open finalist Marcos Baghdatis, a 6-1, 1-0 winner after Janko Tipsarevic quit with a wrist injury.
The Serb said he won the Chennai title last weekend with the aid of pain-killers. Tomas Berdych beat Ivan Dodig of Croatia, who replaced injured Kei Nishikori of Japan, 4-6 6-2 6-3.