The Wimbledon champion progressed to the second round courtesy of a straightforward 6-1 6-1 6-3 victory over his unseeded Japanese opponent at the Australian Open.
I felt freer today than I’ve done in the last 18 months
The 26-year-old looked sharp on his return to Grand Slam competition, hitting 12 aces and 32 winners, after a lengthy injury lay-off following shoulder surgery in September.
And the Scot, who will face Vincent Millot for a place in round three, felt in positive mood after coming through his opener unscathed.
“The signs have been good in practice and did everything solid,” Murray told BBC Sport.
“I felt freer today than I’ve done in the last 18 months.
“I’m confident I’m going to be OK, but these hard courts, these tournaments are tough on the body so it’s going to be a test for me.”
However, Murray did express his concerns about the sweltering heat in Melbourne, with temperatures peaking at 42.2C.
“You’re obviously a bit nervous and apprehensive about it,” Murray added.
“For a number of reasons for me, I was nervous because this, for me, was a big test playing in these conditions.
“Obviously, when the shadow came across the court it cooled down a bit but the air is extremely warm.
“It’s not the easiest conditions I’ve played in. If you were playing on the outside courts in the sun, that would have been worse.
“Most of the players are conditioned well enough to last in that weather for that amount of time but doing it to three or four hours is tough to recover from.”
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