Andy Murray believes he is already reaping the rewards of his back surgery.

The Scot went under the knife in September after experiencing problems on and off for 18 months, particularly on clay.

Murray played his first grand slam match since the operation against Go Soeda in the opening round of the Australian Open on Tuesday and he could scarcely have been more impressive.

The 26-year-old was on court for less than an hour and a half in his 6-1 6-1 6-3 victory and struck 32 winners.

He said: "It's not every single shot that my back hurt on before but certain shots I'm a lot freer in the movement just now. I hope that continues.

"That was the whole point of having the surgery. So if I was still in pain and stiff and sore then I'd be a bit worried about the next few years.

"But I'm hoping it was the right decision. I felt freer (against Soeda) than I did for the last 18 months."

Murray is a three-time finalist at Melbourne Park, most recently last year when he was beaten by Novak Djokovic.

But, with only two competitive matches under his belt prior to arriving in Australia, he is having to deal with a large amount of uncertainty along with the usual challenges of a grand slam.

He said: "Going through surgery is different than going through any other sort of injury or break that you have.

"A lot of players don't come back from surgery and are the same player that they were before. That's something that's always in the back of your mind, something that will worry you a little bit and something you'll think about.

"Before the match, you're worried about the conditions, but you're also just kind of praying that everything is good with the back and you can wake up the next day and all is good."

Murray played in the worst heat of the day on Tuesday with temperatures soaring above 42C, so the 26-year-old will have been delighted to learn his second-round match against French qualifier Vincent Millot will be played in the night session on Rod Laver Arena.

Feliciano Lopez, who Murray has beaten in all seven of their previous meetings, is the only seed remaining in the fourth seed's section, and should he get past the Spaniard, his fourth-round opponent would be one of Stephane Robert, Michal Przysiezny, Blaz Rola or Martin Klizan.

A quarter-final meeting with the likes of Roger Federer or Jo-Wilfried Tsonga would be a big step up in standard, therefore, but Murray is not worried about being undercooked.

He said: "In these conditions you want to win fast. Whether I've played a lot of matches or not, every player would want to get off the court as quick as possible.

"I'm well aware if I go further in the tournament, if I win my next match, the matches are going to get longer and tougher. I'm still kind of waiting to see every day how I'm going to wake up.

"I'm confident that I'm going to be okay. But these tournaments over best-of-five-set matches on the hard courts, over two weeks, it's tough on the body. So it was a good test for me."

It is rare that avid tennis watcher Murray plays an unknown opponent but 27-year-old Millot stumped even him.

Ranked 267, Millot's five-set win over Wayne Odesnik in the first round was his first victory in the main draw of a grand slam.

Murray said: "I know he's left-handed but I haven't played or practised against him before, I haven't seen any of his matches.

"I'll try to watch a bit of video of his match to see how he plays. But I'm glad he won."

The last comment was a thinly-veiled reference to the unpopular Odesnik, who served a doping ban in 2010 after being caught bringing human growth hormone into Australia.