Roger Federer eases through to the second round after a 6-3, 6-2, 6-1 win over Steve Johnson.
It did not take Federer a great deal of time to overcome the American, who could do little to combat Federer, as the Swiss marched on following a routine straight sets victory.
And although there was a slight rain delay in the opening set, it took Federer just 1 hour and 22 minutes to complete the straightforward win.
"I just haven't played proper matches in many, many weeks, and a lot of guys, probably 95% of the guys, are coming here with matches," Federer told reporters.
"For me really the first three rounds are key to get going, to get used to the pressure, stay calm, when to save breakpoint or 30-all points or whatever it may be, or just to stay calm if you're down a set and a break or whatever it might be.
"This is sort of the unknown that can be a little bit scary at times. But today there was none of that because I broke early each set and was able to get on a roll, play freely after that ... I felt like I had the game under control."
The third seed launched his campaign for a record 21st Grand Slam title and showed no signs of rust as he played his first competitive match since losing to Greek Stefanos Tsitsipas in the ATP Finals in November.
The 38-year-old broke his opponent's serve early in each of the three sets and closed out the match when Johnson hit a return long.
Despite blustery conditions, Federer served superbly from the start and hit winners at will against Johnson, who is ranked 75th in the world, and he was as ruthless under the closed roof at the Rod Laver Arena after play was interrupted by rain.
A six-time champion at Melbourne Park, Federer will take on the winner of the match between French qualifier Quentin Halys and Filip Krajinovic of Serbia in the second round.