After India abjectly capitulated for 161 on the first day in Perth, their top-scorer with 44, Virat Kohli, vented his frustration at those who had questioned his technique and temperament. Less than two days later as India stumbled towards a heavy defeat, Kohli stood firm amid the wreckage. When he was last out to complete a collapse of four wickets for no runs in seven deliveries, he had made 75 out of a total of 171. It was Kohli's highest Test score. After the match, he spoke of his relief at finally producing an innings of substance.One innings later, Kohli has scored his maiden Test century. It is a huge achievement, considering what he has had to endure in Australia. Last year was spent confirming â and then excelling â in his position as India's first-choice No. 3 in ODI cricket. But in the first two Tests in Australia, and particularly in Melbourne, his ability to survive in Test cricket was questioned by many. With scores of 11, 0, 23 and 9 in the first two Tests, he was a hunted man in Perth. Many called for him to be dropped, but the management wisely persisted with him. In Perth, he top-scored in both innings and now he's scored India's first century of the tour, 116 out of a total of 272. Sufficed to say, Kohli has improved during the course of this tour. In doing so, he has put all insecurities to one side and set about proving that he's more than just a limited-overs wonder. Kohli is a naturally attacking batsman and there will always be an element of risk to his play. It is how he manages those risks that will determine how successful he becomes. The fact that he appears to be a quick learner will help his cause no end, but it is also a good sign that even with a couple of failures behind him, he had the confidence to continue his own game. His ability to pull with ferocity and precision was there to see when the delivery merited the shot but for the most part he played straight and late, and made crease occupation his primary concern. He left well, defended with his head right over the ball and played for time. His first 71 deliveries contained just one boundary, and when, after hitting his second four, he wafted outside off stump, the reaction was a furious shake of the head. Ball by ball, like all sufficient Test batsmen do, Kohli assessed the situation. When the ball was there to be hit, though, Kohli unfurled the prettiest of shots. Peter Siddle was glanced and pulled with ease, each with minimal movement. Kohli's half-century came up, fittingly, with a spanking pull off Ben Hilfenhaus that bisected two short midwickets. Nathan Lyon was whipped with such precision through extra cover that no fielder could recover the ball, and Michael Clarke's part-time offerings were dispatched through and over midwicket with ferocity. Kohli endured a few nervous moments on 99, but kept his cool to bring up his first Test century with a push through the covers. His celebrations weren't a world away from his fiery reaction at scoring an ODI century against Australia in 2010, but this was definitely a more matured Kohli. It was an eye-opening performance from a man who'd been under-estimated after failing in the first two Tests.This 116 wasn't quite in the class of the knocks that the Australians have reeled off this series, but it was a performance of great resolve and substance, the like of which India have failed to produce on tour. As a unit they have mislaid the art of the meaningful innings, the ability to bat out sessions and turn starts into centuries.Gautam Gambhir has not scored a Test century since November 2009, his technical frailties ruthlessly exposed in England and Australia. Virender Sehwag used to score centuries for fun, with 14 of 22 being in excess of 150, but after averaging 18.88 in overseas Tests (excluding Sri Lanka) in the last two years, his claims of being an all-time great have been greatly tarnished. Sachin Tendulkar has gone 21 innings without a Test century. VVS Laxman's career is over and how much longer Rahul Dravid persists is not hard to surmise.A succession of events both on and off the pitch has turned Kohli's role as India's Test No. 6 into a more important one. He entered this series with plenty of questions hovering over his abilities in Test cricket and with the knowledge that Rohit Sharma was right behind him. He now approaches the end of the series as the linchpin of a middle order that has endured some high-profile struggles, with his appetite for runs and mental strength affirmed. Before the 2011 World Cup, I asked Kohli in an interview about whether he was willing to bide his time before getting the Test call-up. His answer was precise and without hesitation: "I want to mature more before that chance comes. I should be a lot more prepared before I wear the white clothes. Once you go out there and find out that you lack some technical or mental aspect, it would be an opportunity wasted. It would be better to become more mature before you get that Test opportunity."After displaying much maturity in limited-overs cricket, Kohli has taken huge strides in his last three Test innings. As an era ends and the baton passes on, fans of Indian cricket can only hope Kohli has used this tour as a stepping stone for huge success.