The ball slowly went over the net and into the opposite service box, but a perplexed Kyrgios was left rooted to the spot in bewilderment, as did those present in the crowd, while the umpire called "Game, set, and match" in a 6-3 6-4 victory for Tomic.
It could have been worse for Kyrgios, a former Open quarter-finalist who has slipped to 50th in the rankings, and Tomic, three-times a second-week challenger at the season's first major.
The Australian's ranking is up to No. 85 in the world just ahead of his home Slam, while Kyrgios has dipped down to No. 51.
Yet both players have maintained their off-court clashes of the past - notably almost three years ago when Tomic accused Kyrgios of faking an illness to get out of playing a Davis Cup match - are behind them, and considering the relaxed nature of this tournament, it's unlikely sparks will fly when the pair finally do face off across the net.
"It is great to see him back out here as I know he was going through some rough times".
Chastened somewhat, Tomic began to rebuild his game last season, winning his first title since 2015 at Chengdu last September and he appears to be carrying that momentum forward.
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He added how the Canadian governments and taxpayers also provided $11 billion in subsidies to GM at a time when it faced near bankruptcy a decade ago.
In an earlier match, Marin Cilic outlasted Kevin Anderson 6-3, 4-6 and 15-13 in a pro set tiebreaker.
The Australian served five aces, no double-faults and broke Halep three times to reverse two previous losses to Halep last August. "My attitude to tennis is the same whether I won or lose", he said. "She gave me a belting in Montreal".
"I need a few more days to play and train and hopefully reach 100 per cent".
The Australian Open 2019 draw was held early Thursday morning, and it revealed a tough first-round matchup for Milos Raonic and a potential second-round blockbuster for Eugenie Bouchard. Cahill had coached Halep for four years. The pair have never playedon the ATP Tour.
"It was another good training day".
Isner's defeat was another blow to a tournament already deprived of star power by the withdrawals of Gael Monfils, Roberto Bautista Agut and Tomas Berdych and the first-round losses of Chung Hyeon and Denis Shapovalov.