Feel like I'm getting a bit faster with every game: Mitchell Marsh.

SYDNEY -- Mitchell Marsh might be developing the world's worst case of pad rash, but it hasn't affected his bowling. In fact, Marsh is bowling faster and taking more wickets than ever. What was notable during the Boxing Day Test against West Indies was not just that Marsh took a career-best 4 for 61, but also that he was regularly clocking above 140kph. That's a handy trait for a Test No.6 to have.

Marsh has spent much of the summer sitting in the change-rooms, padded up and waiting for the end of enormous top-order partnerships, and the fact that he has scored only 88 runs in five Tests is testament to his lack of opportunity, not form. But Australia could hardly be happier with the way Marsh has bowled, so much so that the coach Darren Lehmann said Marsh could play as a third frontline fast man in Sydney, where two spinners are likely.

"It's quite flattering to hear that, but the biggest thing for me is just playing my role," Marsh said. "Sometimes as the fourth seamer, it's about coming on and tying up an end and giving the blokes a rest, and then [Tuesday] I had an opportunity to bowl a few more overs and I saw that as an opportunity to work as hard as I could for the team and to get a few wickets."

The speed with which Marsh was carrying the ball through to wicketkeeper Peter Nevill was especially notable in comparison to the frontline fast bowler Peter Siddle, who was generally operating slower than Marsh. Siddle was carrying an ankle problem but even so, there was no question that over the past year Marsh has worked his way up from medium-pacer to genuine fast-medium.

"Over the last 18 months, I've worked really hard with [bowling coach] Craig McDermott to try and get a few extra k's on my bowling and certainly over the last few months I've felt like I'm just getting a bit faster and faster in every game that I play. Obviously the more I bowl the more I'm learning about my body and how far I can go. Hopefully I've set the tone now for the rest of the summer."

As well as pace, Marsh's aggression was notable at the MCG, where he roughed up the in-form Darren Bravo with bouncers. "I think if you're bowling bumpers at 120kph, like I normally do, it's not quite as scary," Marsh joked. "You don't have to use it all the time but there are certain times in games and certain periods when you see an opportunity to get up someone and I suppose it was one of those days."

Marsh and Nevill have both found themselves with limited batting...