Kohli has been practically unstoppable in limited-overs matches recently. In just 194 ODIs, he is level with Ricky Ponting with 30 centuries, the second-highest in ODIs. He also racked up back-to-back hundreds during India's 5-0 mauling of Sri Lanka recently.
Smith, meanwhile, has the better Test record, averaging nearly 60 as opposed to Kohli's 49.55. Smith was also the highest run-scorer (499, including three hundreds) from either side when Australia toured India for four Tests earlier this year.
"In limited-overs cricket, I think Virat is ahead of Steve, but just by that much. Smith, I believe, is a better Test batsman," Clarke said during a media interaction in Delhi on Tuesday. "I think over the next few days, everybody would want to speak about Steve Smith vs Virat Kohli, but at the end of the day, it comes down to one thing, and that is the team that wins. It doesn't matter who makes the runs - Kohli or Smith. At the end of the day, your job as a captain is to win.
"Another focal point, besides their batting, is their assessment as leaders. And honestly, at the moment, I think it's very even at this stage of their careers. Two young captains, two very good players, and they both continue to improve. Along with that, like I said, what's important as a captain is that your team in winning. And at the moment, Kohli's team is winning. Smith needs to find a way to crack that momentum early on in the series and needs to find a way for Australia to pick it again."
India go into the five-match ODI series on the back of impressive recent ODI form. After making the final of the Champions Trophy, they recorded series wins in the West Indies and Sri Lanka. In contrast, Australia are still nursing the wounds of a group-stage exit in the Champions Trophy, and only managed to draw the two-Test series in Bangladesh. Clarke said the upcoming series could provide a blueprint to Australia's preparations for the World Cup in 2019.
"I think it's time for the Australian team to really decide how they want to approach the 2019 World Cup. The likes of Smith, David Warner… they've got to work towards finding what is the right technique and style for these players.
"Are they going to be an aggressive team? Will their top order go hard or will they try and consolidate for 50 overs and have wickets in hand? There's still plenty of time before the World Cup, but the whole squad really needs to start now. The players need to identify their roles during this India series. Hopefully, they attain success and carry it forward into the Australian summer.
"Their form over the last few months has been very inconsistent. They haven't played as much cricket as they would have liked. The Australian fans expect Australia to be at the top of the tree, to be No. 1 in the world, and if we can beat India, I think 4-1, and then we will get there. It's a great chance for Smith to get their form going."