In the opening round of this Ranji Trophy season, Tamil Nadu had begun well in the second innings after being bowled out for 87 in the first dig on a greentop in Lahli. Dinesh Karthik was at the heart of his team's effort to set Mumbai a competitive target, and had begun by hitting a four and a six. But he was out trying to paddle-sweep Balwinder Sandhu, a seamer, and his dismissal triggered Tamil Nadu's collapse from 129 for 2 to 185 all out.

Mumbai nearly botched their chase of 97 and got there with only two wickets in hand. When the dust settled, Karthik's shot selection came under the scanner. At the end of the match, one of the first people Karthik sat down with for a debrief was a member of the opposition, Abhishek Nayar. Nayar, incidentally, was the calm head that had steered Mumbai through a nervy chase.

Nayar says he discussed the process and not the consequences with Karthik. "I don't focus on whether he played a good or bad shot, it's just why he played that particular shot and I try and understand that," he tells ESPNcricinfo. "I don't think he played a shot like that in the season going forward, not because I told him not to but because he understood why he could have done something else."

This wasn't just the vanquished seeking out the victor for a one-off chat. For over a year, Nayar has been Karthik's go-to man for counsel. Nayar helps Karthik with his pre-match preparation, and together, at the end of every match, they review Karthik's performance. Whenever Karthik finds time, he takes the flight to Mumbai to stay with Nayar and train with him. During the times Karthik can't be there physically, Nayar is just a phone call away. It's a unique mentor-pupil relationship between two active cricketers, who, apart from a season for Kings XI Punjab in 2011, have rarely played on the same side.

At 31, Karthik is two years younger than Nayar, and they have known each other since their Under-16 days. Karthik can't remember when he decided to approach Nayar, but they have always been good friends and so they "kind of got talking."

"A lot of times people didn't understand me that well, but I thought he really connected with me very well," Karthik tells ESPNcricinfo. "He was also in a space where he was willing to give me some time and hear me through. I can definitely say after I started talking to him I've become a much better player, a far more consistent player."

Nayar doesn't reveal the details, but says he plans specific sessions in accordance with Karthik's needs at different stages. While most of his work with Karthik during a tournament involves discussions on the cricketing side of things, their off-season preparation features physical fitness and mental conditioning.

"He normally stays with me and we plan a training programme," he says. "Then, during games, he calls me up before every game, and in the two-three days break we plan them and we plan the games as well. He likes everything to be specific and immaculate, and wants to know why we are doing a certain thing and how it will benefit him.

"During the IPL, it was about planning his innings, his mindset before the game and understanding what situations he may face, and discussing the bowlers before the game. I wasn't part of the IPL last year, so it was easy for me to watch every single game he played. Before any tournament, we focus really hard on his preparation, his programmes and what he needs to do as a build-up to the tournament."

Abhishek Nayar raises his bat after reaching a century BCCI

While Nayar can't put a name to the kind of work he does - "I just call it helping out someone" - Karthik feels "life coach" is an apt title. "For about 15 years, it's Mr Basu, who has been the Indian team's trainer, who has always been there for me," he says. "He has definitely been one of the most important persons.

"In the last 15 months, Abhishek has been a huge help. He is a lovely guy and we are very fond of each other. He and I have one thing similar - we pushed ourselves a lot more than most people would have, in different ways. He has probably pushed himself a lot more physically. I have tried to mentally push my barrier.

"He is somebody who isn't as talented as some cricketers, but he has really overachieved in terms of where he's ended up, playing for India. He was a touch unlucky sometimes not to get picked [for India], but he's had a great cricketing journey. I don't think I've given him any sort of help whatsoever. If anything, he's given away a lot of time and energy to me, but not vice-versa."

Nayar says he has always derived satisfaction helping players achieve their dreams. Making tough decisions at a young age about his cricketing career, he says, taught him understand life better. "Since a young age I have been the kind of guy who gives advice to his friends, and have taken important decisions also in my family," he says. "I have had faced a lot of difficulties growing up - there are a lot of personal things I don't want to talk about - so understanding life from my point of view and from my family's point of view kind of helped me."

Karthik says he aspires to do something like Nayar. "I'd like to be somebody who can help a lot of people and genuinely that's one of the things I want to do," he says. "I don't want to just share my experiences - that is one small aspect - but I want to hear people out and genuinely give them feedback."

Nayar says his relationship with Karthik doesn't involve financial considerations. "I am not a very money-minded person. So, it is for the love of the game and the fun of helping someone," he says.

So, is mentoring a career option for Nayar, who already runs a cricket academy in Mumbai, after his playing days are over? "I don't know, man. I haven't thought of anything right now. I never started doing it thinking Icould keep doing this later on. I do it because I enjoy it. It depends how it goes, it is going well so far and guys are doing well and very happy. As long as I can keep doing it, it doesn't matter."

Nayar also assists other players, such as Srikar Bharath of Andhra and Abhimanyu Easwaran of Bengal, in their preparation. "He's helped so many people. In the last couple of years, one big name most people know is Rohit Sharma," Karthik says. "Rohit always trains only with Abhishek. Off late, there is Shardul Thakur and Shreyas Iyer from the Mumbai team."

According to Nayar, his team-mates don't mind him helping out players from other sides as long as they are beneficiaries of his assistance as well. "For me, it doesn't matter you are playing against each other. In this game, everyone knows what each other's flaws are," he says. "If I can help someone out, so be it. It doesn't matter if he scores a hundred or a zero against us. I think helping someone out is more important."

Nayar and Karthik, though, abide by a mutual code where they don't communicate with each other before a Mumbai-Tamil Nadu game. At Lahli, they spoke only after their game concluded, and with the semi-final in progress, they haven't talked for more than a week now. On the field, though, they go hard to each other. Nayar was visibly disappointed when he beat Karthik's bat in the first innings without finding the edge.

"I think he wants to take my wicket very badly, and I definitely want to score runs off him, so that way the competitive edge is there for both of us," Karthik says.

Nayar too says he doesn't let friendship come in the way of competition. "On the field, I am playing for Mumbai and he is playing for Tamil Nadu and we are opponents," he says. "I didn't have the chance [to sledge DK during the Lahli game] because he didn't bat that long. But, next time if I am in the position and if I feel I should sledge him, I will. But, I know sledge doesn't have an impact on him."