Virender Sehwag saw the Test batsman in David Warner before he realised it himself. Drawn towards a Twenty20 career before his methods matured, Warner was in Delhi when Sehwag helpfully suggested the man synonymous with cricket's shortest form would make a better player in its longest.

The conversation startled Warner, at that stage still yet to receive a baggy blue cap for New South Wales. But Sehwag was prescient, for little more than two years later, Warner is about to open the batting for Australia in a Test match against New Zealand. It has helped that others, Greg Chappell among them, also saw the potential for far more than 20 overs' racy batting.

"Two years ago when I went to Dehli, Sehwag watched me a couple of times and said to me, 'You'll be a better Test cricketer than what you will be a Twenty20 player'," Warner recalled. "I basically looked at him and said, 'mate, I haven't even played a first-class game yet'. But he said, 'All the fielders are around the bat, if the ball is there in your zone you're still going to hit it. You're going to have ample opportunity to score runs. You've always got to respect the good ball, but you've always got to punish the ball you always punish'."

The conversation with Sehwag may have been the start of Warner's drive towards batsmanship worthy of a Test match, but it was also helped along by Chappell. On the Australia A tour of Zimbabwe, Cricket Australia's national talent manager told Warner his brief sessions in the nets were not going to prepare him for lengthier innings, and encouraged a more longwinded approach. It worked.

"In Zimbabwe he sat down with me and said 'what are you going to do when you bat today'. I said I'd bat for the 20 minutes we normally get and try to get myself in," Warner said. "He said 'if you're going to get yourself in, how are you going to play your shots then, you'll just work on getting yourself in and that's it'. I said we don't really have that much time, and he replied 'you've got as much time as you want, you're a professional cricketer, we've got net bowlers here', so I batted for two hours, three hours and it all made sense to me.

"If you're going to score hundreds you've got to put time in the nets. Troy Cooley [the tour coach] would say to me a few times 'you've got to get out [of the net] then go back in', so I did that a few times, prepared like it was lunchtime or a bit of a break for 30-40 minutes, then went back in for another hour or two. I was always conscious of not getting out. In a couple of those sessions I only got out once, and that was to a loose shot from one of the spinners. I really knuckled down there."

On that same tour Warner coshed 211 against the Zimbabweans, batting for eight hours to do it. Like a young adult developing a taste for vegetables after a youth spent avoiding them, he found that first-class runs could feel more rewarding, and that the compressed nature of T20 had made him yearn for the wide open batting expanses of a match played over four or five days. Lately, Warner's newfound judgment has been noticeable in his T20 innings too, resulting in a consistency of scores he never managed in 2008-09, the summer that had Warner thrust into the national team.

"I enjoy it, I wouldn't actually say it's easier than Twenty20 cricket or one-day cricket but you've got so much time. You're not rushed at all. You don't have to score runs," Warner said. "The wide ones you usually go after in one-day or Twenty20 cricket and they're the chances that you give, you're getting yourself out. In four-day cricket, you shouldn't be getting yourself out at all like that.

"A good ball is going to get you out, but a lazy shot you shouldn't get out like that, you should be kicking yourself. That's one thing I pride myself on, if I'm getting out I'm not playing a loose shot. It tends to happen a bit with spinners, you think 'oh I can get some easy runs here' but you've got to have your footwork switched on and be able to play back or forward and not get carried away.

"I've adapted my game in four-day cricket to be as technical as I can and make sure my defence is as good as can be. That's the most important thing in four-day cricket, if your defence is good, the runs will come. As people have probably noticed in my one-day and T20 stuff, I've started to do that as well, I get myself in, my first 50 is coming off probably 40 balls, instead of 21 or 22 and that's a reason why I've been so consistent in my last few innings, because I'm not going after every ball straight away."

Warner's difficulty in obtaining a New South Wales cap made him hungry for runs, but also forced him to find the right way to get them. "When I got my baggy blue I was very happy and proud," Warner said. "It is amazing how in 18 months how everything can turn around, whether it is playing one-dayers or Twenty20 cricket for Australia, how close you can be to the baggy green."