The new and improved Shane Watson

Shane Watson has evolved into a Test bowler of international class by delivering the sort of stuff his younger self would have scoffed at. "Too slow," the young Watson might have said, or "too boring". Too good, in fact.

In the first Test against Sri Lanka, aided by a devilish Galle pitch, Watson returned match figures of 5 for 30 from 19 overs, splintering the hosts' middle order with a trio of lbws in the first innings then nabbing the critical wicket of Kumar Sangakkara with a brute of a ball in the second.

He did it all with shrewd reverse-swing, suffocating accuracy and at a pace only mildly above medium, far removed from the faster but ramrod straight offerings he first exhibited for Australia. Watson now admits a more measured approach in his early days as an allrounder might have resulted in his avoiding the surfeit of injuries that seemed to have stunted his playing career.

"I was trying to bowl at 170kph. And I got nowhere near it," Watson said. "As a younger guy growing up, I just wanted to bowl as fast as I possibly could because that's what I thought would get me success. Unfortunately I didn't really move the ball off the square, and all I did was angle the ball in, so it wasn't that effective.

"I have learnt from my mistakes in the past. If I had my time again I probably would have been smarter at how I approached my bowling. I now realise how important moving the ball is and it would have made a little bit of difference on my body, as a younger guy, if I was a little bit smarter in how I bowled.

"There was a period of time when my body didn't allow me to bowl 100% every ball. I realised physically I couldn't do it so I had to find another way to be effective and in the end its worked out better. I have had more success: I have been able to move the ball and conserve my body a bit."

Watson mark II first began to emerge for Australia on the 2008 Test tour of India. The visitors spent eight weeks in the country without winning a single match, but Watson's use of reverse-swing far outstripped that of any of his fellow bowlers. He has continually worked on the art ever since.

"It probably comes easier to me than some of our other bowlers," Watson said. "I think it really comes down to a bit of luck at my release point, to be able to get the seam in the right position and how I release the ball. My action helps.

"Reverse-swing can play a big part; this was probably not as flat a wicket as I have bowled on but on a normal flat wicket, if the ball is reversing, it can make [batting] difficult. It gives me an added dimension."

Missing from Watson's game in the first Test was a significant score, as he was spun out in the first innings and then victim of a questionable choice of stroke in the second. An admirably frank character, Watson is happy to agree that he is less likely to be as effective with the ball in matches where he has batted for a long period.

"I suppose it depends whether I get runs," Watson said. "I didn't get any runs this match so I had to try and have some impact and input into the game. Sometimes it's not always going to be my day with the bat and that's the great thing about being an allrounder.

"I knew in this game I was going to be quite fresh because I didn't get any runs. I knew I would have plenty in the tank to have a crack at bowling."