Sourav Ganguly believes 2014 Australia tour was turning point in Kohli's career

Although Australia won the 2014 Test series 2-0, Kohli scored an impressive 692 runs in eight innings at an average of 86.50. Ganguly said it was the start of the new Kohli and compared his form since to Rahul Dravid. 

"I think the tour of Australia in 2014 completely changed Virat Kohli the batsman. Four back-to-back hundreds in that series, I think that was above all. His performance in that series was by far the best I've seen in a long long time. And I don't know whether Kohli himself can match that again," Ganguly told India Today.

"It's about being at the peak, it's a situation in an athlete's career where you just hit it. There's no when, there's no how. It's just a patch you hit and you make the most of it. Rahul Dravid from 2001 to 2005 scored runs all around the world and it's the same thing with Virat Kohli."

Over the last year, Kohli has scored 1215 runs in 12 Tests at an average of 75.93 that has seen his career average soar over fifty. He also scored a double hundred in each of the three preceding Test series.

The biggest question on everyone's mind after the T20 series against England, where Kohli struggled for form, was whether the 28-year-old could recreate the magic of the year gone by. In the true Kohli way, he proved all his doubters wrong with yet another double century, this time against Bangladesh.

After the one-off Test against Bangladesh, India gear up to face the mighty Australians. While Ganguly said that the Aussies would prove to be a tougher nut to crack, he was confident that the kind of form Kohli is in he could score double centuries against the Australians as well.

"Australia will be better than Bangladesh. They've got the fast-bowling attack to exploit these conditions. The likes of Mitchell Starc, Josh Hazlewood, and the rest will get the ball to reverse. But once again the challenge for Australia will be spin. That's the key in the sub-continent, you have to play spin well and bowl spin well," Ganguly said.

"But Virat Kohli is good enough to get double hundreds against Australia also. So it doesn't matter what the opposition is, here you have a player who can get runs in all conditions and get runs against the best teams in the world. He will be up and ready against Australia because he knows that's a big series."