NAGPUR: India host Australia in a hotly anticipated four-match Test series starting on Thursday in Nagpur.AFP Sport looks at three key battles that could decide who comes out on top in a clash between the world's two top cricket teams.VIRAT KOHLI VS PAT CUMMINSVirat Kohli has triumphed over his extended lean patch from last year and his match-up with fast bowler Pat Cummins, the Australia skipper, could light up the series.The batting maestro has hit four tons since breaking his 1,020-day century drought in last year's T20 Asia Cup, but hasn't been able to bring his white-ball form into Tests.Read AlsoOur fast bowlers have been good in all conditions: Pat CumminsWhile there is so much talk about spin bowling, Australia captain Pat Cummins said his side should not forget about their intimidating pace bowling attack.An exemplary leader, Cummins has on the other hand been in the best Test form of his career, claiming 29 wickets in nine Tests over the past 12 months.Cummins has got Kohli out five times in Tests, but the home hero will be looking to hit back in his backyard."I am really looking forward to seeing Kohli versus Cummins. That's a fantastic match-up," former Aussie quick Jason Gillespie was quoted as saying by the Hindustan Times."When Virat comes out to bat, I would love to see Cummins take the ball and go at him straight away. That will be great theatre, two wonderful cricketers at the top of their game."DAVID WARNER VS MOHAMMED SIRAJSparks are expected to fly when David Warner, an explosive left-handed opener, faces the seam and swing of rising star Mohammed Siraj.Read AlsoDavid Warner 'extra motivated' to do well in India, AshesBack among runs after scoring a scintillating double hundred in his 100th match during the Boxing Day Test against South Africa, opener David Warner said that he is not done yet and is 'extra motivated' to do well in the highly-anticipated Test series against India and the Ashes next year.Siraj, 28, got Warner out twice during his 2021 debut in Australia and went on to take 13 wickets in three matches.He has since grown in stature to regularly lead India's pace attack in the absence of the injured Jasprit Bumrah and has bagged 46 wickets in 15 Tests.Warner has struggled on Indian pitches, with a batting average of 24.25 in eight Tests in the cricket-mad country. His overall Test average is over 46 across 101 matches.Both men have something to prove in the coming series and Warner said last year that "winning in India is key".INDIAN SPINNERS VS AUSTRALIAIndian spinners at home are a challenge for any visiting batsman, but for Australia's in-form opener Usman Khawaja the task may well decide the fate of the series.The Islamabad-born Khawaja handled spin with aplomb in Pakistan last year and led the tourists to a 1-0 series win with his 496 runs, including two centuries in three Tests.Read AlsoIndia vs Australia: Will spinners decide the winners?A Test series in India invariably boils down to the spinners. The last time the subcontinental giants lost a series at home, to England in 2012-13, spinners Graeme Swann and Monty Panesar wreaked havoc. This time around, there’s a feeling that the Aussies might just be better prepared. And it has aThe 36-year-old left-hander recently notched up his 4,000th Test run in a match against South Africa in Sydney, where he was 195 not out.Khawaja is especially wary of Ravichandran Ashwin, who has enjoyed great success against left-handed batsmen, telling The Sydney Morning Herald: "Ashwin is a gun."He's very skilful, he's got a lot of tricky little variations, he uses the crease quite well too.""But it's one of those really good challenges," Khawaja added.