Tokyo: Defending champion Andy Murray blew away the cobwebs with a 7-6, 6-4 win over Croatian Ivo Karlovic on Tuesday in his first tennis match since winning last month's US Open.
The Olympic gold medallist said winning his first Grand Slam title in New York had forced him to change his objectives and become more "responsible."
"I was so, I don't want to say 'obsessed' with winning a Grand Slam, but it was so important to me," world No. 3 Murray said. "Sometimes during the year in certain matches I haven't done myself justice. I felt after the US Open (I needed to) reset some goals.
"I was always focusing on the next Grand Slam rather than every tournament and every match I played. Now I feel like I can hopefully concentrate better, take more responsibility for my performances in every tournament throughout the year."
The Scot said he felt no different having finally won his first grand slam after losing in four finals. "It didn't feel a whole lot different (stepping on court as a Grand Slam winner)," said the 25-year-old.
"Hopefully with time that will come," added Murray, who reached his first Wimbledon final this year before exacting his revenge on Roger Federer in the Olympic final in London. "I think where I will feel it more will be if I'm getting to the latter stages of Grand Slams. Hopefully I will start feeling more confidence to go on to win."
Murray, who was on court for an hour and 38 minutes, will face Slovakia's Lukas Lacko in the second round.
Japan's Kei Nishikori survived a fright against countryman Go Soeda, the eighth seed squeaking through 4-6, 6-2, 6-3 to the relief of Tokyo organisers in two hours 29 minutes.
Nishikori, who reached his first semi-final of the year in Kuala Lumpur last week, next plays Spaniard Tommy Robredo, a 6-2, 6-4 winner over Finland's Jarkko Nieminen. Big-serving Milos Raonic hit 10 aces in a 6-4, 6-4 victory over Czech Radek Stepanek.
Russian qualifier Dmitry Tursunov piled more misery on Australian hope Bernard Tomic, recently given a dressing down by Davis Cup captain Pat Rafter, beating the 19-year-old 6-4, 7-5. Former Australian Open finalist Marcos Baghdatis scraped past Ukrainian qualifier Sergiy Stakhovsky 7-6, 7-5 to reach the last 16.