The 22-year-old allrounder stamped himself as a successor to the injured Shane Watson with his 89 from 83 balls against Zimbabwe on Monday, his 109-run stand with Glenn Maxwell at more than 12 an over giving an irresistable glimpse of what he might be capable of at next year's World Cup and beyond.

That he did it batting as high as No.3, and can hold down a spot as the side's fourth seamer, explains why coaches have been hoping for years that the more extroverted of the Marsh brothers would get his game and his lifestyle in order in time for the prestigious 50-over tournament.

"The thing we like most about Mitch Marsh at the moment is his bowling," chairman of selectors Rod Marsh said when Marsh was picked in the squad for Zimbabwe.

"He's capable of opening the bowling or coming on through the middle overs and can do so with good pace, which is pleasing. It's the sign of a true allrounder if they can be in the side for either their bowling or batting and he is certainly getting close to that, which is great for Australian cricket."

Jacques Kallis is one of very few modern cricketers who could bat in the top order and be a frontline seamer and stay on the park, and it's too soon to lump Marsh with such a comparison. But the groundswell of excitement around him is not suprising given he appears to have put behind him the disciplinary problems of two years ago, when he was sent home from the Centre of Excellence and dropped from the Perth Scorchers team after a night out at the Champions League for his 21st birthday.

His biggest challenge will be to stay fit, having worked hard under Justin Langer in Western Australia to overcome serious hamstring injuries.

"I don't think 'turned a corner' is the right way of putting it, but we all know that I've had a few ups and downs," Marsh said after his innings in Harare. "My biggest focus over the last 12 months has been progressing both as a person and staying on the park. It's been a great few months.

"So it was special [to make his first international 50]. I just had the role to get us as deep as I could, and obviously if we had wickets in hand at the end, with the batting we have we could apply some pressure to their bowlers.

"I thought 'Maxi' and all the other guys at the end batted really well to get us to a great total. It was certainly good fun to watch. I was very happy being at the other end. He's a special player and that was a great innings from him.

"I've got my body at the stage now where it's hopefully going to be able to handle the rigours of international cricket and if I stay on the park hopefully I can continue progressing."

Maxwell's 93 from just 46 balls included an audacious switch hit, but Marsh also has the power game needed for the short formats. This was just one game, in a 198-run victory against a modest Zimbabwe attack, but Watson's ankle injury has given him a chance to nail a spot ahead of the World Cup.

He is undaunted by a South African attack with Dale Steyn and Morne Morkel in it. "I'm certainly not scared or anything, I'm looking forward to the opportunity to face those guys. Hopefully I can play a role for the team."

Captain Michael Clarke is likely to miss Wednesday's game against the Proteas due to hamstring issues, but when he does return Morkel will be waiting.

"I think Michael will know that Morne is out there to try and hunt him down," said South Africa bowling coach Allan Donald. Morkel fractured Clarke's shoulder when they last met in the series-deciding Test in Cape Town. "It's always in the back of your head. When you've had one bowler that has done that to you before, he might do it again."

Australia's first game in five months also delivered a reminder of Mitchell Johnson's destructiveness - with the bat. Commentators had to dust shards of glass off themselves when Johnson cracked the window in front of them with a brutal, straight six.