With T20I, ODI series done and dusted - the action show shifts to the Test arena which many believes will be a litmus test for world number India team as they gear up to face New Zealand in challenging conditions. Before the start of the main action, various permutations and combinations have already started doing the rounds as experts are giving their verdict on India's best XI for the series opener in Wellington on February 21. <p></p> <p></p>Jumping in the debate, senior off-spinner Harbhajan Singh has thrown his weight behind Shubman Gill's inclusion in the playing XI for the first Test. Harbhajan feels Gill's stellar performances in First-Class cricket (for India A precisely) deserves special mention and he should make his Test debut on the New Zealand tour. With scores of 83. 204* and 136 - the 20-year-old Gill has presented a strong case for himself and has shown great versatility while batting at various slots. <p></p> <p></p>Meanwhile, Prithvi Shaw, who is back in the Test squad after 16 months, is also a contender in the playing XI with his equally dazzling repertoire of strokes. <p></p> <p></p>"Shubman should get his chance since he has been part of the team (as reserve opener) for quite a while without playing any Test match," said Harbhajan. <p></p> <p></p>Their journeys have been intertwined since the U-19 days but in next 10 days, Shaw and Gill will provide skipper Virat Kohli and coach Ravi Shastri with a lot to ponder while fighting to be Mayank Agarwal's opening partner in first Test against New Zealand, starting February 21. <p></p> <p></p>With Rohit Sharma being ruled out due to a hamstring injury and the in-form KL Rahul surprisingly ignored by the outgoing selection committee, India could go into the series with Agarwal, who has so far played nine Tests, as the senior opener. <p></p> <p></p>India's woes could be compounded as Agarwal, despite his superb initiation in Test cricket, has been in wretched form, bagging a pair (0 in both innings) of the 'A' Test in Christchurch and failing in all three ODIs. He also had a quiet couple of Ranji Trophy games. <p></p> <p></p>However, Harbhajan feels that Agarwal should continue as the main opener. "Mayank is a proven player in Test cricket and a top batsman. He understands his game very well. Just because of three ODI innings and a practice game, you don't drop him. It doesn't work like that," Harbhajan explained. <p></p> <p></p>"He has been scoring lots of runs wherever he is playing, so I feel Mayank and Shubman should start in first Test," he added. <p></p> <p></p>But, former India wicketkeeper Deep Dasgupta has a contrarian view and wants Prithvi to start in the playing XI. "I fully understand that Shubman is in great form but remember one thing. It was Prithvi who made his Test debut before even Mayank. He did well and was first choice in Australia before getting injured," Dasgupta's countered Harbhajan's argument. <p></p> <p></p>Dasgupta, who was in New Zealand as an analyst, feels Prithvi looked in great touch throughout even though he didn't get a big knock. "If Prithvi has been out injured, then he should rightfully get his place back in the side. Shubman has to wait." <p></p> <p></p>Asked if Shubman, whose range of strokes is way more than Hanuma Vihari, could be accommodated in the middle-order, both replied in the negative. <p></p> <p></p>"No, in the middle order, Vihari is a better bet. He has done nothing wrong in his limited opportunities. Shubman's real impact is when he is opening," said Harbhajan.