An aggressive run-up, a high jump and a solid action ensured that Zaheer Khan was consistently clocking over 140kph in his debut series. That Zaheer was a left-arm seamer made him even more eye-catching. There's something about left-arm bowlers that their right-arm counterparts envy - the ability to make a straight ball look special. Since about 80% of top-order batsmen around the world bat right-handed, the regular angled-across delivery from a left-arm pacer is enough to create doubt, which is what Zaheer did initially. His wrist was firmly behind the ball but at an angle (towards first slip), and that meant that everything he bowled went in only one direction and followed the same path - away from right-handers and in to lefties.

I remember facing him in a Duleep Trophy game in Mohali. The pitch was green, the weather cold and Zaheer on top of his game. Till then I had never faced bouncers that threatened my safety, for there was always a way to get out of harm's way. But Zaheer's angle meant that Virender Sehwag and I had to be fairly quick to get out of the way. Zaheer's bouncers were also very accurate in height - short enough to bounce above the shoulder but not enough to sail over the head.

Since Sehwag had faced Zaheer before, he told me to only play deliveries that pitched outside or on the leg stump and to leave the rest alone, even if they were pitched on the middle stump. Leaving a ball pitched on middle stump is tricky. What if the ball comes back in instead of going away? But Sehwag was right. None of Zaheer's deliveries came back in, and that made survival possible.

But it also meant that Zaheer had to reinvent his bowling style, for if we could decipher the threat and survive, top-quality batsmen around the world would do the same.

And that's exactly what he did during his county stint with Worcester. He compromised on pace to develop the ability to swing the ball back into right-handers. The wrist, once again, was firmly behind the ball, but this time it was in the direction of the stumps and not facing first slip.

The period between 2007 and 2011 was Zaheer's best phase in international cricket, in terms of wickets and impact. While he could still crank up the pace whenever he wanted to, he chose to do so selectively. Bowling in county cricket not only taught him to master inward movement but also helped him learn the art of staying effective even while bowling at 60-70% of his capacity.

Most good bowlers will tell you that bowling well and taking wickets are two different things and that the former doesn't count for much if you don't master the latter. Since Zaheer was still bowling a lot on featherbeds in India, he had to find ways to conserve energy for when real opportunities to take wickets presented themselves, which was when the ball got old and started reversing. That's when he mastered the art of bowling at 70% in the afternoon session without leaking too many runs. He would bowl fuller (but not full enough for it to be a half-volley) and wider (not wide enough to be left alone without entertaining a thought of flirting with it) to a packed off-side field. It sounds simple in theory but needs a lot of control to execute in a Test match, because top-quality batsmen find ways to score runs when the bowler isn't operating at 100%. During these spells Zaheer would still slip in his accurate bouncer once in a while to keep the batsman honest, but never those searing yorkers that take a lot more out of a bowler than a bouncer.

Once the ball started to reverse, Zaheer would come into his own. He was one of the few international bowlers who managed to hide the shine till the very last point of release, and that made him too hot to handle. Being a left-arm pacer helped, because going round the stumps was always an option, which he used quite effectively. It was a delight to watch him but a nightmare to play him once the ball got old.

The only flip side to Zaheer's bowling style in the latter half of his career was that there was just too much of a load on his upper body, for he was no longer running in as fast as he used to, and there was virtually no follow-through.

To gauge a fast bowler's decline look no further than his jump. If the height of the jump is considerably reduced, you know he isn't the same bowler anymore. That happened to Zaheer. His bowling began to rely solely on his upper body strength and his strong wrist.

The immediate effects of it were visible on the tour to Australia in 2011-12. While he was still quite a handful with the new ball, his old ball simply didn't have enough of the old venom to get wickets. He couldn't crank it up at will anymore, and that might have had a lot to do with the spate of injuries he had suffered.

Zaheer was among the top three Indian fast bowlers of all time. In fact, I'm tempted to put him ahead of Javagal Srinath. Zaheer in his pomp was a complete bowler. His knowledge of the craft of fast bowling will be handy for the next generation of Indian pacers, and it will be prudent to bring him into the fold as soon as he's ready to start his second innings.