Smith's sensational century

Steve Smith is in career-best form and the run glutton shows no signs of slowing down in the Test series against India.

Smith served up the greatest one-day innings of his life at the MCG on Friday night, a polished 104 guiding Australia to a three-wicket win over South Africa that clinched the series.

It was the latest impressive chapter of a purple patch that extends back to the Test recall he earned on Australia's disastrous tour of India last year.

"It's up there," the 25-year-old replied when asked if he feels in the best touch of his burgeoning career.

"I'm pretty happy the way it's all going.

"My whole batting in general has improved a lot over the last 12 months.

"I'm premeditating a lot less, I'm playing each ball on its merits and just looking to bat time.

"Every game I play for Australia I'm just looking to keep winning games for them and keep getting better."

Smith's second man-of-the-match knock in a row came at No.4.

It's a position he could take in the Test batting order on December 4 should Michael Clarke be ruled out of the first Test with a hamstring injury.

Smith, viewed as Clarke's likely long-term replacement as Test skipper, could also be given the captaincy in Brisbane although he doubts it will happen.

"Brad Haddin will be the captain I'm assuming (if Clarke is unable to play)," he said.

"He's been vice-captain for a long time and he's a terrific player. He'll step into his shoes and do a great job as well."

Smith said patience would be key if he's to deliver some big scores in the four-Test series against India.

"It's very important, particularly in my game, to not flash at the wider balls," he said.

"Giving myself a chance and leaving well."

Smith was controversially left out of the one-day series opener in Perth and was keen to make a point after being recalled to replace hamstrung Clarke.

"I was a little bit disappointed, but since I've come back I feel like I'm hitting the ball really well," he said.

Proteas coach Russell Domingo paid tribute to Smith, who rebuilt his side's innings at the MCG after Australia slumped to 5-98.

"He's on top of his game and ... it was one of the better hundreds that's been scored against us for a period of time," Domingo said.

Steve Smith's hot streak:

ONE-DAY INTERNATIONALS:

* 474 runs from 11 innings at 47.40 in 2014

* 190 runs from 3 innings at 63.33 v Pakistan in 2014

* 187 runs from 3 innings at 93.50 v South Africa in 2014

TESTS:

* 565 runs from 11 innings at 56.50 in 2014

* 327 runs from 9 innings at 40.87 v England in 2013-14

* 269 runs from 5 innings at 67.25 v South Africa in 2014

*174 runs from 4 innings at 43.50 v Pakistan in 2014.