World number seven Marin Cilic tested a knee injury with the best possible result on Wednesday, but temperamental Nick Kyrgios' poor start to the season continued at the Kooyong Classic.
Former US Open champion Cilic, who led Croatia to a Davis Cup trophy in November, skipped last week's Maharashtra ATP tournament to rest.
The wait was worth it as he posted a gritty 6-3, 4-6, 15-13 win over Kevin Anderson, recovering from 2-7 down in the new final-set tiebreaker that will be used at the Australian Open for the first time next week.
Under the rules, the first player to win at least 10 points by a two-point margin takes the match.
Cilic, who was beaten by Roger Federer in an epic Australian Open final last year, said his knee was not a worry.
"The knee felt slightly more stiff than usual, maybe that's from a first match," he said.
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"I need a few more days to play and train and hopefully reach 100 percent." Cilic added: "It took me some time to recover from the emotional end to last season with the Davis Cup.
"I'm feeling a bit rusty, but I'm hitting the ball well and feel on good form." South African world number six Anderson was battling jetlag after arriving in Melbourne following a title victory at the weekend in Pune, India.
He is also relaxed about his form heading into the first Grand Slam of the season next week.
"It's good to play a competitive match, it's the best way to acclimatise," he said.
"I want to be as healthy and fresh as possible heading into next week. This is my eighth match of the season, so I'm not worried about that."